A Most Rudimentary Photo Voltaic System

This post is going to be rather general in nature, it is essentially going to go over setting up a most rudimentary diagram of solar panels on a structure. For some this may seem overly basic or a repeat of some of the other posts, but it really is going to try encapsulate a series of ideas into one post. Some of the protective devices are not shown, this is for a number of reasons to keep things simple. Sophisticated systems should have fuses or circuit breakers; systems that are set up in a manner where there is no chance for an incorrect polarity connection can omit the “back Diode” Some of the regulator circuits use a regulator IC, and those can be expensive, however a simple effective voltage regulator can be achieved with a single MOSFET and a variable resistor for small systems, and is the basis in the system in the image below, if the current available at peak time for charging is greater than 80% of the current rating for the MOSFET used, you can put them in parallel as is shown in one of the earliest blog posts (2010 or 2011). In some parts of the world it may be one or a couple of 15 or 30 Watt panels and a battery with some “power LEDs” or discrete LED lamps. I will cover those too, but not in great depth in this post. This specific post is the result of some conversations I have had via Facebook chat with a few people in Africa, plus some recent news stories from Deutsche Welle and a couple other sources. Politics aside, because part of the problem with some of the UN’s efforts to bring solar power to a number of African countries is the lack of people with a fundamental knowledge of what they need to do to effectively install a system. This I hope will help change that because the systems as a whole, are quite simple to install, maintain and make use of when using low voltage lighting devices.

If you know how automotive charging systems work, there are parallels to most alternative energy systems. If you understand basic lighting systems, there are only some minor detail differences to lighting systems with alternative energy.

There will be some images produced for this post, and no offense is intended to anyone’s intellect- the drawings are rather simplistic mainly because the drawing program I am using is very simple. Plus sometimes images can convey the concept even if the person viewing the image is unable to speak your language, or speak or read English.

When dealing with solar panels, you want them to be positioned so the sun is perpendicular to the panel for the most amount of time if the panel is mounted to a stationary position. You want the panels secure enough to withstand expected winds. If panels are going onto a metal roof, a shingled roof, or flat roof, use brackets to secure the panel to the roof using some manner of sealant on any fasteners that go through roofing materials to protect the roofing and any supporting materials. In areas where the panels are going on a thatched roof, you want to secure the panels to some supports that are stuck into or embedded in the structure of the walls if possible for most secure installation. In such a situation, binding cord, fiber (or fibre), or even wire scrap can be used and loops attached to the mounting frame should be used when possible for tying ropes or cordage to. If there is no other option, you can have the securing material cross over the face of the panel that is toward the sun- this does slightly reduce the power output of the panel. However the panel itself must not be drilled- but it’s supporting frame can be drilled. Keep leads apart at all times and avoid contact with the wire ends if the panels are being installed in daylight conditions because the panels will produce power when the main surface is exposed to sunlight, and sometimes the size of the panel is large enough to produce current flow adequate to weld steel, or kill.

The image is a most rudimentary system. If the panel is about 30 Watts or less, you may be able to omit the voltage regulator only if you can check electrolyte in the battery and add water as needed to keep the plates covered. If the wires are clearly color coded and correct (verified with a test meter), the “Back Diode” can be omitted provided the battery connections are never reversed. The back diode will serve 2 purposes. 1) prevent discharge of the battery through the panel when it is not charging. And 2) protects the panel in the event battery terminals get reversed when a battery is changed.
rudimentary system

Single FET regulator with notes.

Single FET regulator with notes.

If additional panels or batteries are added later, they just need to have the polarities matched or the wire colors matched. Adding panels will increase charging current, so you may want to go with a larger current rated MOSFET, or they can be put in parallel too. I do have some early blog posts on how to increase the power handling of the regulator.
doubled up MOSFETS
The diagram can be used for general troubleshooting purposes as well. My hope is this is useful in undeveloped or underdeveloped countries, where parts “may” be available, but are not always cheap or close by.

Two types of LED setups are shown on the drawing. More can be added, but the further you get from the battery, the more resistance exists in the wire used so you may need to reduce the number of LEDs in series the further from the battery you get, and this also limits how many you can put in parallel on that same run of wire.

The color of the LED’s has some affect as well. The best results if “white” LEDs are not available is amber or yellow, followed by orange. Red and blue LEDS can be added to green LED’s to create a light that is almost percieved as white if their light projection cones overlap. Otherwise red or blue LEDs by themselves can be used for lighting. The advantage with red LEDs is they do not alter night vision, and if that is important to you, then by all means use red. Blue can also be used, but it is not quite as good as red with regard to night vision. The intensity (or light output) of LEDs does vary, so choosing the brightest you can find is the best approach. If you do not have the specifications available to you, if you happen to have some “2032” or “2025” cells salvaged from a computer main board handy, these are adequate for compairison type testing of LEDs from a bulk bin. Pick the brightest ones of course. This is a really simplistic approach, but it works. I will cover more about LEDs and Diodes in one of the upcoming “Back to Basics” posts.

The main blog. If you start from the begining it will make more sense, even if you know little about electronics.
The first post from which much was expanded from, which is probably where to begin if you have some background with basic electronics.

If you are not well versed in electrical components, or even new to electronics, this may help as they are a back to basics series that covers primarily that which is important to alternative energy systems.
https://altenciruits.wordpress.com/?s=%22Back+to+basics%22 This is the search option that will list the “Back to Basics” series of posts. The first post in that series was “Wire” and things progress from that.

The tangential blog.

The passive solar blog- outgrowth from some projects of mine.

Posted in altencircuits, Alternative Energy, Alternative Energy Circuits, Alternative Energy Circuits for "Homebrew", Basics, Charge Controllers, Charging Circuit, Emergency power option, Solae Power, Solar Power, Uncategorized, Voltage Regulation | Tagged , , , , , , , , | 2 Comments

Back to Basics: Capacitors, an Introduction.

Back to Basics: Capacitors intro.
This is just a cursory discussion about capacitors, how and where and why they are used in alternative energy systems. If you are expecting a full dissertation on capacitors with all the formulas and calculations, you will be disappointed. I am just covering the basics with minimal math and focusing more on the discussion of how and where they may be used, some of the types and where to find them, and not too much else as the main focus of this blog is alternative energy systems.

Capacitors will block DC, Once a capacitor has charged, current does not flow. Capacitors will allow AC to flow, which is why they are used between amplification stages and are also used for noise supression in automobiles as well as for protecting electrolytic capacitors from high energy RF interference as they pass that energy to ground more readily than the larger capacitances will to protect the larger capacitors.

The short answer is this: Capacitors hold a charge. They are not batteries, though some types of capacitors are used similar to batteries in some situations where a only a slight drain exists in order to maintain a memory in things like VCR’s, DVD Players, radio tuners, etc and more recently supercapacitor technology is being deployed in Europe in transit busses where they average about 5 Kilometers between charge/charging stations and can charge in 10 to 15 seconds.

If the “supercapacitor” type is shorted, it will discharge in milliseconds, and usually can be recharged with no harm done to it. This charge and discharge cycle is NOT the direct result of a chemical reaction as it is with batteries.

Batteries on the other hand are a storage vessle depending upon a chemical reaction to produce Electromotive Force. “Primary cells” such as you use in radios, MP3 players, etc are intended as “single use” or “Primary” batteries because they are made in a way that is not intending for them to be recharged. And there are “Rechargeable” batteries or Secondary cells or batteries. Technically, a single cell, such as you would use in a flashlight is just a “cell”, 2 or more become a “battery”. While it is parsing definitions, it is just how they are. If you look at a lead acid battery, it is usually made up of cells, nominally 2 volts each cell- 6 caps, vents, covers is a 12 volt nominal battery. 3 caps, vents or covers is a 6 volt battery. Each cap cover or vent is one cell, and with a lead acid battery one cell is 2 volts. (If the wall of the cell is breached so the electrolyte between those cells can mix, this develops an electrical path, those 2 cells effectively become one cell.) These cells take time to discharge because a chemical reaction needs to take place for EMF to exist in the circuit, and they take time if rechargable, to recharge- however a dead short sufficient to draw full current will discharge the battery quickly, if not cause an explosion of the battery outright, or cause some internal failure, or cause a fire if left in that shorted condition for any length of time. If you totally discharge these, or charge them at a rate in excess of their design, they pose a fire hazard for various reasons for one, and for two, they may become damaged internally as internal plates heat and deform, which can be the end of the battery, either by boiling out the electrolyte, burning out a bar between cells or damaging the plate supporting structures.

So they are not universally interchangable, but some supercapacitors have been assembled in series parallel configurations adequate to operate a small radio even though they were not designed for this, as well as the busses mentioned above. Capacitors are essentially just 2 plates of some conductive material and a dielectric between the plates (air can be a dielectric, but it is not a perfect one.). Capacity is measured in Farads, microfarads, nanofarads (more often in european equipment) and picofarads. They follow the nomenclature of the Metric System. The capacity is determined by the area of the plates and the distance between them. As plates get larger or get closer together, you increase the capacity. And value is reduced as plates get smaller or spaced further apart.

Failure modes of capacitors are common and how they are made, the materials used, etc determine some of the ways they can fail. All designs can fail “open”, usually the result of a mechanical defect or excessive stress on the leads that can pull them apart internally. All designs can “short circuit”, some are more difficult to achieve this condition when they are made from a metalized film as these will ablate the aluminum layer applied to the film away from the area where an arc occurred through the dielectric. Oil types use the oil part as part of the dielectric and for cooling, and can leak out their oil content, which reduces the effectiveness of the dielectric leading to a shorted condition or a resistive condition. Sometimes this oil can contain PCB’s which were introduced in World War 2 to increase thermal stability of the oil. Not all capacitors contain PCB’s though, and more on this a little later. The oil types can leak, and some can explode when they fail.

Electrolytics are another type of capacitor and these can “dry out”- which just means the electrolyte has evaporated from the capacitor. This leaves them vulnerable to shorting out if the potential gets high enough to break down or break through the remaining dielectric material. When the electrolyte dries out, capacity usually reduces as well as the potential for shorting as the integrity of the dielectric is reduced as they dryout.. Some of the older (pre 1975) Electrolytics contain PCB’s and should be handled carefully if they appear to be leaking. These typically are larger values of capacitance and are used for filtering in power supplies or to provide instant power when the circuit demands it.

PCB’s (Poly Chlorinated Biphenyls) are not naturally occuring, and can potentially cause cancer. The only safe manner of disposal is in high temperature fires- which are not achievable without correctly designed furnaces, so do not simply toss them into a firef.

When capacitors do fail, they sometimes leave clues- some will explode leaving just the leads left sticking from the circuit board (Tantalum capacitors are famous for this.), electrolytics will sometimes bulge the top or vent out of the bottom of the capacitor. Some electrolytics will also have a brown substance ooze from a breach in the presure relief seam on top, though they can vent out of the bottom as well, and electrolytics can explode. Some of the vintage , and many larger value capacitors have a pressure relief port filled with a rubber plug to release if a problem develops- often Hydrogen Sulphide is smelled when one of the rubber seals is breached. Paper types will have the wax melt out of them if they got hot (directly or indirectly), and sometimes this indicates a failure, sometimes not- they should always be checked when this is spotted. Paper types usually fail as an open circuit, but if the paper has been breached by a voltage spike, they can short as well. Most of these do not contain PCB’s but they do use Castor oil- which can leave you with an upset stomach if decide to unroll them. Worst case is vomiting as Castor oil is usually used as a “purgative”.

Now there is a concept of the “Perfect Capacitor” which has no resistance in the circuit, and it will charge and discharge instantly. However the reailty is that capacitors are going to have some amount of “Effective Series Resistance” or “ESR”. ESR is not something to worry about when you are rebuilding something all that much if you are matching other characteristics such as ripple current, leakage, or heat range, or type- such as an “audio” capacitor. ESR does have some influence in “tuned” circuits or bandpass circuits and in Class D amplifiers, but otherwise in most circuits, ESR is not going to have much affect if any at all in the circuit. Some people strive to have as low of ESR values as possible when rebuilding an audio amplifier, but this is more out of a personal preference on their part because manufacturing techniques have improved, and even some of the low cost general purpose types have a lower ESR than some of the better grade capacitors made 20 or more years ago. The way to visuallize the ESR value is to just imagine a resistor in series with the capacitor. The reality about ESR is that it really is not as critical a factor in selecting replacement capacitors for a repair when other more important factors are given a priority.

ESR is also not an adequate measure of merit either. However ESR can be a factor if you are designing from the ground up, but keep in mind other factors are more important in some areas of a design than others. In something like a power supply filter- ESR is not crucial at all unless it is a “Flyback” type of switching mode or switch mode power supply where timing or resonance may be affected. In circuits where there is an RF component to the potential to be filtered, such as in “Switch Mode” Power Supplies, you need to use capacitors with a high “Ripple Current” rating, otherwise the RF breaks down the dielectric and the capacitor fails. If you are designing one of these supplies, you may want to add some small value capacitors in parallel to bleed off some of that RF component, but ESR itself value has little influence in most power supply designs in the filtering aspects. Resonance or timing aspects- yes, ESR becomes a consideration but you can compensate with other components in many cases.

In short, people often give ESR more importance than it really needs, and when working on high end audio, or you are building something for quality audio, Sonics of a capacitor are a more important consideraion, but people hear things differently and listen for different things in music when evaluating capacitor types. In most cases people will not hear any difference between dielectric types. Unless you are building the amp and making compairisons as you build it, then you might hear it. If you don’t, don’t worry about it because most people will not hear it either.

With some of the newer “Class D” audio amplifier circuits, low ESR capacitors are usually indicated by the IC chip manufacturer in some cases to compensate for the limited gain designed into the IC chip and sometimes to reduce the influence of that ESR in the PWM timing aspect of the Class D amplifier where the Pulse Width Modulation circuit which has a rather narrow range of acceptable capacitance and resistance tollerance to maintain accuracy.
Though as mentioned above in repairs, low ESR is otherwise not crucial if you are matching some important characteristic such as “Low Leakage” (which is common in audio circuits) and “High Ripple Current” which is important in switchmode power supplies, or “higher” or “extended temperature range” capacitors, or recapping the audio amplifier audio string with newer “Audio” grade capacitors. Most capacitors are rated for 85 degrees C, there are some that are rated for 105 degrees C. Replacing capacitors rated for 105 degrees with one rated 85 degrees is not a good idea unless you know the Ripple current rating is higher with the lower temperature rated part and that the operating environment will not approach 85 degrees C in extreme conditions. Extended temperature range is usually encountered in automotive and aerospace. In those cases, the temperature range is typically expected to be from -40 C to +105 C (or higher in some cases) for temperature range of operation.

In audio circuits, you want a “Low Leakage” type of capacitor. Many manufacturers also make “Audio” specific types which have some “sonic” characteristic in mind as well as low leakage. “Leakage” itself is just a measure of current that passes through the capacitor once it has achieved a fully charged state, and you can visualize it as a resistor parallel to the capacitor. A “Perfect Capacitor” in a DC circuit will have zero leakage once fully charged, yet the reality is there will be some small amount of current that passes through the capacitor for various reasons. Low Leakage is a more important rating than “low ESR” in general with audio repairs, and while some may argue this, the fundamental reality is that this is a true statement because the quality of capacitors has increased in the past 20 years. And unless a modern IC manufacturer specifies Low ESR capacitors be used, it can safely be assumed that the new capacitors have a lower ESR than the original capacitors in the circuit if the circuit is older than 20 years.

Many High Ripple Current capacitors also have a low leakage value, and coincidently a moderately low ESR, but you really have to scour data sheets to determine which ones have all of those qualities, and in this way you can improve the sound characteristics of low end audio equipment at minimal extra cost. Most low end audio can be improved significantly by upgrading all the electrolytics in the “audio string” (any part of the circuit where the audio signals pass through) by upgrading the transistors and Op Amp ICs with low noise versions as well, however the street value will not improve, but if you own one and it has sentimental value, it is an option to bear in mind if you want to keep it around longer.

So as good of a quality as many capacitors are today, they are not even close to “Perfect”, but in many ways they are better than those that came before them even 10 or 15 years ago or more in that materials are better, quality controls are better, new materials are being used that surpass the performance of the older materials, quality control is better, and most important for the consumer- their prices have come down as a result of the economies of scale that those other improvements have brought forth.

Those capacitors that use an electrolyte use one that is not conductive, so it is usually an oil base, or just an oil; Castor oil is common, as is just mineral oil. And in others it is a proprietary chemical combination that is both liquid and non-conductive. One type that uses an electrolyte and are used in power supplies primarily are called “electrolytic”, and these do have a polarity. While the charge they hold or discharge is not dependant on a chemical reaction, they will explode if their polarity is incorrect for the circuit. However there are some “non-polarized” electrolytics which are made a little bit different from the regular types and they can be installed in the circuit with no worries of polarity matching. Older radios had “Wet” Electrolytics in the portion of the filter that is in the circuit right off the rectifier and an actual liquid electrolyte; and “Dry” electrolytics (which still have an electrolyte) in the later filter stages and elsewhere in the circuit. This combination was done as the Wet Electrolytics were better able to handle surge currents at initial power up than the “dry” types. The electrolytics have a higher energy capacity typically and higher capacitance values in most cases than those that are used in coupling or decoupling or bypass circuits. The earliest AC radios had large oil impregnated paper and foil filter capacitors that will get warm in operation, but if the capacitor begins to short out, it can lead to a failure of the power transformer and the tar can melt out of it as well.

In most of these alternative energy circuits covered, when electrolytics are used, they are often used as filters, because they can discharge their energy into a circuit to even out the potential (smoothing), or in cases of their use in audio outputs- to supply extra current instantly when needed for larger signals. They have a higher energy density than comparable values made from other materials and are therefore typically smaller than comparable capacitors made even 20 years ago.

Capacitors also are used to block DC. In audio circuits for example, you can isolate amplification stages with capacitors. They will allow the AC energy to pass through, but they effectively block DC current and are used for this purpose to decouple circuit stages and to allow the AC/RF/audio signal to pass to the next stage. The size of plates and proximity of the plates to each other also determine the amount of energy transferred and their capacity in terms of Farads, microfarads, nanofarads and picofarads. The LED power supply I made and have a few posts on here utilizes this aspect of capacitors to pass AC power through to the LEDS- though it is rectified and has a power smoothing filter capacitor to eliminate flicker, the primary current regulation or limiting is achieved via capacitors.

When a DC potential is applied to a capacitor, the capacitor will take on a charge up to a point, so if you have a DC voltage source, a capacitor with one lead attached to the battery for example and voltmeter completing the circuit back to the battery, the meter will bounce (if analog) and a digital will show a slight increase in voltage momentarily and then return to zero. The battery is charged at this point when it can take no further energy in, and until the load (the meter) is shunted/bypassed with another load to initiate a discharge it will hold that charge for a while, and some types will tend to discharge faster than others. If the charged capacitor is shorted across it’s leads, it will discharge instantly. If there is adequate capacity you will hear a spark as it discharges. If the capacity is high enough, an arc can form. In other words, if you make the mistake of touching the terminals of a large electrolytic filter capacitor, or a physically large capacitor, you will recieve a jolt of high current DC because the capacitor is discharging across part of you that isin contact with the terminals, and this can cause physical harm. So they should be handled with care in the event you encounter one that someone has charged up and left out as a joke (a very bad joke), or was removed from a circuit without discharging it. Many will also have a tendency to develop a potential by just sitting, which is why some large capacitors are shipped with a shunt resistor installed in order to bleed off this energy.

If an Ohmeter is placed across the terminals of a cacitor of sufficient size, the battery from the meter will charge the capapcitor and you will see the needle initially deflect to nearly zero ohms and then fall back as resistance increases as the capacitor charges.

With AC, the energy from the AC source will transfer across the capacitor, but actual electron flow does not occur- there is a dielectric insulator of some sort to prevent that up to the point of the breakdown potential of the dielectric itself (arc over or short circuits). If you look at the “Capacitive Chargers” and the “Capacitive power supply for LED arrays/fixtures”, you will see the capacitor in series with the LED load or battery load circuit. If applying a DC source, once that capacitor in series is charged, no current will flow in a “Perfect Capacitor”, and minimal current will flow with a real capacitor, but because the current is alternating in polarity, it will swing negative and discharge that capacitor and also charge it with the reverse polarity doing this continually, which is how current can be limited by the capacitor because it is limited by it’s capacity as to how much energy it can store.
Capacitive power supply for LED fixture.Capacitive battery chargerAdditional notesSome cautions

If you are familiar with pith balls and a “Leyden Jar” which is a demonstration with static charges, when the leaves inside are standing apart, they have a charge of electrical energy stored upon them, and it is essentially similar to the stored energy concept of a capacitor. On a Macro scale, lightning is a similar example of what happens when the dielectric “fails”. In the case of lightning, the air above the ground is the insulating dielectric, but there is a point where that insulating ability breaks down, and the arc of lightning is the result. However, the clouds have accumulated potentials even after the lightning strike which nature will try to achieve a state of equillibrium with more lightning.

You can think of the energy transfer from the one capacitor plate to the other as much the same things a when you hold your foot on one croquet ball to send the other ball (that is touching it) off to some other part of the croquet pitch- your foot and the ball under it are analogous to the dielectric, the mallet being the incoming charge, and the ball shot across the lawn is the electron energy transfered. The energy is the only thing transferred, not the electrons.

Additionally, while the electrons are isolated by that dieletric layer, if you were to make contact with the wrong lead of the capacitive charger and your body completes the circuit, you will feel the jolt of current as you would if grabbed a bare conductor connected to the mains power, which is why the capacitive power supply circuit as a battery charger would never even come close to getting a positive safety rating from any of the safety rating agencies because there is no isolation from “mains current”. The variant that is used as an LED power supply “could” achieve that status if the exposed conductive portions of the assembly are grounded and the “hot” side of incoming power is covered in such a way that prevents contact with the hot side (which is one of the LED supply leads).

Capacitors have a rate of discharge over time based on their capacity, which when coupled with a resistance, or an inductance in parallel (priarily), the rate of the equalibrium state of the circuit for charging/discharging (or Resonance frequency) for a given set of voltage values of the circuit can be calculated, but rather than weight this discussion down with a great deal of math; right now I will just explain that “Resistance Capacitance” or “Resistor/Capacitor” filter (RC filter for shorthand) and “Inductance Capacitance” filter (LC for shorthand) each function with a capacitor together to create a circuit that responds to a specific “frequency of resonance” based on that time factor of charge/discharge over time when plotted on a graph. It forms a resonant circuit that can be used for timing or filtering a specific frequency or range (High pass, Low pass, or a specific frequency or range). Put a different way- an equilibrium is achieved where the capacitor is charging via applied power and the “load” is discharging that capacitor along with the resistance or inductance parallel to it at a rate where the capacitor neither fully charges, nor fully discharges either until power is removed. Changing the frequency of the applied power (If AC) will change that point of equilibrium as will changing the capacitance or the load.

Small inductance coupled with small capacitance resonates at a higher frequency than larger values of either component or just larger values of both. The reason is the larger capacitor or inductor take more time to achieve full “charge”. The same is largely true with a resistor and capacitor circuit, though a higher resistance will yield the higher resonant frequecency, and even though the resistor is not charging or storing energy, it is discharging the capacitance continuously. Because of that time factor that is characteristic of this combination in circuits, these combinations can be used for filtering rectified AC into DC, or for tuning a radio to a specific station for example. (Radios that tune with a Varactor diode use a variable resistor for tuning, but it is that applied voltage that changes the capacitance of the Varactor and effects it’s “tuning” frequency.

When that capacitance is coupled to a motor (which is in some aspects an inductor), depending on the motor type and where the capacitor is in the motor circuit, and it’s capacity, that capacitor can either be part of the motor’s “start winding” circuit, part of the “Motor Run” circuit, or as a power factor correction circuit (usually associated with the “Run” circuit.). With the case of a three phase motor coupled mechanically to a single phase motor with the single phase power applied to that single phase motor and applied across one “leg” of the three phase motor, it will create a magnetic field within the motor and capacitors in parallel to those other 2 “legs” charge and discharge in the other two phase windings to simulate the three phase power that you can apply to a second three phase motor to operate it ( a form of rotary converter). That first three phase motor is acting as a 3 phase dynamo. You can run a 3 phase motor inefficiently on single phase power as well; directly with capacitors across the 2 other legs, but that is an entire blog post in itself.

Additionally, with an AC synchronus motor, such as found in older electromechanical clocks, fans and phonograph motors, a capacitor of relatively small value can be used to alter the speed of the motor as well. When across the leads of the motor, it will slow the rotation slightly. The capacitor can also be put in series with the motor winding, but unless it is of adequate capacity, the motor will not run nearly as fast as without it and slower than if it is in parallel, and since it’s capacity will also affect the speed of rotation as the capacitor limits current flow, it can be used to limit the amount of available transferable energy (the simplest notion for power factor correction.) to that motor winding.

Now with the “Stargate motor” (I am not giving the guy free exposure so you will either have to take my word for it, or look for them on Youtube), one of the demo videos you find on Youtube, where the guy thinks the capacitors are working like batteries and he has put them series…. He is effectively installed them into the motor circuit in a manner consistent with a power factor correction capacitor from what I can tell of his wire tangle and description. The real problem is a lack of understanding on the part of that individual in that video as to what the capacitor is really doing in that circuit, not to mention his lack of understanding what a capacitor does, or how or why motors work. It would have been helpful to see the full schematic of how he wired it to evaluate what he did, and where his misunderstanding began and it would have been of value to see some oscilliscope waveforms at various points of the circuit as it would make it easy to explain what is really going on other than the simple fact he is just altering the magnetic flux/magnetic field of the motor with those additional magnets and plates and essentially changing the motor from it’s original construction by that alteration. Now please understand I am not trying to “bash” him, it is just that what he is doing with his magnets is little different from taking a 6 volt Ford Generator armature and installing it in the statioary field frame of a 12 volt Ford Generator- where when you “motor” the generator, that difference in magnetic flux between those two generators gets the armature spinning much faster than either the normal 6 volt generator or 12 volt generator would with their correct corresponding battery and armature. I fault the US education system for that.

Putting capacitors in series does nothing to increase their actual EMF energy out- but it does effectively increase the spacing between the plates thus reducing capacity and increasing the potential you can apply across the stack of capacitors.

Putting 2 capacitors in series that have the same working voltage rating effectively doubles the working voltage, and if they are of the same capacity, you cut the total capacity in half. Capacitors in series have their effective capacitance calculated thusly:


Capacitors in series

When you have a smaller value capacitor across the leads of an inductor with DC applied on one “side”, that resonant feature of the capacitor trying to hold it’s charge while being discharged by the impedance of the resonance winding of the coil of wire can be utilized as an electric fencer- in this configuration it is often known as a “weed burner” as weeds that contact the bottom charged wire tend to be singed as they continue to grow into the wire. Below is a simplified schematic sans any safety features or specific values and should not be used as a construction guide as I am only illustrating the basic design of that device.

weed burner

weed burner

Capacitors in parallel, their working voltage values are unchanged, but the capacities are additive as you are effectively expanding the plate area.

Between the other types of capacitors, be they paper, styrene, silver/mica, polyester, polypropylene, metalized paper, etc. (the dry types)- they can be used interchangably, but unless you pay attention to the orientation with the conductive chassis, you may introduce some noise (or not if you are careful). The only real caveat is to make sure the working voltage (WVDC or WVAC) is adequate for the circuit. WVAC ratings are lower than WVDC for some capacitors that can be used with either type of circuit in large part due to the explanation of RMS values for AC discussed earlier.

When working with electric motors that utilize a “Start ” capacitor or a “Run” capacitor, these are designed for the current they are expected to see and are not interchangable with each other, or other types even though their internal construction is largely the same as other Electrolytic types, electrolytes and dielectrics differ plus motor capacitors are often the least well made of capacitor types. These and Power Factor Correction types just get a light mention here as they are not crucial to the discussion of smaller alternative energy systems. But if you do repairs on power tools and power equipment/machinery, you will encounter them. For further in depth discussions on power factor correction, there are numerous application notes produced by motor and capacitor manufacturers and some companies that make motor control IC’s and circuits. Some vendors also have educational video modules addressing these topics as well.

Lastly a mention of “Polymer” capacitors, which are a newer development and are finding uses in high ripple current applications and elsewhere and are smaller than comparable values of conventional electrolytic capacitors and they are fully interchangable with the older electrolytics. There are also “Tantalum” capacitors, which are a high energy density capacitor akin to electrolytics as well, but use Tantalum in their construction. Tantalums are unforgiving, and I do not cover them here because I do not use them much at all, but they still have some uses in instrumentation, audio, and a few other applications.
Plus there are the “Aerogel” or “super” capacitors, which are high value and small working voltages which have been limited to use in applications similar to battery cells for memory applications, and were mentioned in passing above for powering a small radio but due to their fast charging rate and low current requirements to maintain newer “volatile” memory circuits that type has been limited somewhat in their development and deployment in some ways as the manufacturing techniqes are changing with the result many are considered obsolete now as semivolitile memory IC chips are in use now (and reducing parts counts on the printed circuit board are a way to cut production costs.).

In short- Most of the capacitors in use in voltage regulators and “Solar Controllers” used in alternative energy systems in the voltage or current regulation are there for smoothing purposes and to eliminate line noise, and in some of the sophisticated solar controllers, they are there for energy storage for pulse charging. Those used in power inverters are there for smoothing, timing, wave shape and to bleed of some noise present from the inverter.

There are books written about capacitors full of formulas and various calaculations etc. The bottom line with capacitors- You can use Mica/ceramictypes, film types, paper, polyester, styrene interchangably- When you see a band on one end- it is the outer foil. When used in audio circuits, it makes the capacitor self shielding when the outer foil when tied to ground. You can also use these to replace some smallerelectrolytics when space and values allow it.


an old house renovation blog

The main blog.
the begining point place to start

The tangential blog.

The passive solar blog- outgrowth from some projects of mine.

Posted in Back to Basics, Basics, Uncategorized | Tagged , , , , , , , , , , , , , ,

Back to Basics: Electrons and Electron Flow

This back to basics is about electrons and electron flow.

It seems counterintuitive but when you are discussing DC potentials, the excess of electrons are at the positive end of a battery cell (+), or the positive terminal of a power supply or battery charger, the anode or “plate” of a rectifier tube (thermionic valve) This is a hold over from the early days of electricity experimentation.

Now “Current flow” is from negative to positive. It may be easier to think of the negative terminal of a battery(-) as actually having an excess of holes that the electrons fill in when there is a complete circuit for electron flow to occur, or rather “hole flow”. This is what you look at when discussing semiconductor or “Solid State” devices at the level of the silcon wafer or level of the atoms.

It is when you get into electronic theory where electron flow is crucial. The thing to keep in mind if building your first system is to be not too concerned about electron flow inside of components themselves, you are just wanting to make sure that you have a complete circuit and that external polarities of the components are in the circuit correctly. You only worry about what is happening inside of the device using switching devices (Thyristors), transistors, and Vaccum tubes (Thermionic Valves), and this is where matters of biasing come into play. When the mentioned devices are used in audio circuits, measuring circuits, etc, is the time when biasing becomes a concern and since the focus of this blog is more about building alternative energy systems, the details of biasing are not going to be covered here, there are numerous textbooks that discuss the details.

This becomes vitally important when we discuss diodes and LED’s.

The main blog. If you start from the begining it will make more sense, even if you know little about electronics.
The first post from which much was expanded from, which is probably where to begin if you have some background with basic electronics.

If you are not well versed in electrical components, or even new to electronics, this may help as they are a back to basics series that covers primarily that which is important to alternative energy systems.
https://altenciruits.wordpress.com/?s=%22Back+to+basics%22 This is the search option that will list the “Back to Basics” series of posts. The first post in that series was “Wire” and things progress from that.

The tangential blog.

The passive solar blog- outgrowth from some projects of mine.

Posted in Back to Basics, Basics, Uncategorized | Tagged ,

I have been busy with a large project….

There are a few posts being written, and some artwork being created for one of them, but they will be a little while in the making until the big project is done, which has been occupying my time since the last post. I thank you for your patience on this.

Posted in Uncategorized

Back to Basics: Resistors

Back to Basics: Resistance and Resistors:

Wire has resistance. Different metals used as conductors have different resistances for a given length. In other words, Iron has a different resistance per foot for a diameter we will just call “X” now, and other metals of the same diameter “X” and length have different resistances as well. Some are better than other at conducting, Copper, Silver and Gold are the best conductors, but still have some inherent resistance. But 2 meters of 1mm gold wire will have less resistance than the same diameter and length of silver, and silver will be better than copper, and copper will be better than aluminum, which is better than iron. Steel being a generic term for alloys of iron, steel alloys will vary in their resistance as well. Carbon is not a metal, but will conduct electricity to some extent. The precious and semi-precious metals, in addition to their being able to conduct electricity, will also conduct heat well as well.

Resistors are made from a number of materials, some are temperature sensitive and those compounds or mix of compounds or alloys are used for temperature variable resistors or “Thermistors” which find uses as thermal sensors in automobiles, electric thermometers, etc. They can either increase in resistance as they warm (Positive Temperature Coefficient or PTC) or they can develop lower resistance as they warm (Negative Temperature Coefficient (NTC)- it depends on the device design. And metal oxides with some of those same thermal properties are used for Metal Oxide Varistors or just “MOVs” and “Inrush Current Limiters”, which are protective devices that will usually conduct electricity that exceeds threshold values of the device design parameters, (with the latter having a negative temperature coefficient closer to a typical Thermistor- only physically larger and useful in audio gear to protect devices from excessive inrush current when initially “turned on”) MOVs on the other hand absorb transient spikes, either those present on incoming power or those caused by transients from simply turning equipment on or off.

Resistance will generate heat, often because EMF is being converted to heat in order for it to be disipated. This is why composition resistors tend to drift in value. To demonstrate EMF heating, you can take 2 bare iron nails, sanitize them in boiling water then wrap the stripped end of the two leads of a power cord long enough to wrap around the nails reasonably securely, and what you have is an electric hotdog cooker (that can never even be considered as safe and will just never be accepted by Underwriters Laboratories for safety certification, and you accept all liability and responsibility if you try this and have bad results: but if done with care and observation of general safety precautions, it is reasonably safe for experimentation.).

Just stick the two nails into each end of your favorite brand of hotdog
and making sure to do this outdoors with the assembly on a nonconductive
item like a large dinner plate, with care- plug it in. The hotdogs get
hot in seconds. Hotdogs are better because they are usually fully cooked
first, so no problem with pathogens in the meat if they do not get cooked
through. The other larger tubular luncheon meats like Kielbassas- you do
at your own risk- but if you do use these larger sausages you want to make
sure they are smoking hot- unplug it periodically to check temperature,
especially at the ends, but never while it is plugged in. Once they are
up to 170 degrees F, the potential pathogens are usually addressed. This
was one of things that used to be in the old Boy Scout manuals. You do want
to be careful because this is a dangerous thing to do because you are not
isolated from mains power, but it is a good demonstration of the effects
of electric current on luncheon meats (or if mishandled- you), plus it
demonstrates the ability of electricity to heat things up not normally
heated that way (for food anyway), and by extension the potential for
electricity to heat electrical wiring that was not intended to be heated up.
The nails do not need to go in very far, about a half inch or so.

Resistors can fail, usually they burn out. However some will go out of tollerance from heat, either indirectly applied, or from that generated from within. Usually when this happens, the resistance increases (rarely does it decrease). Most power types are protected by the materials of the casing to prevent damage to other items in their vicinity if they fail. They should be placed away from other components and off the board if on a printed circuit board. When composition types fail, they usually burn through, which is why flameproof resistors are so common these days- they are coated with a material that will not support combustion.

Resistors are just components that have a resistance value marked on their body by bands of color, or in some cases inked or stamped into or onto their bodies. The three band resistors are most common and they are referenced with the 3 colors closest to one end as shown in the image and read from left to right. The two other bands are described a further down. There are some newer 4 band resistors and those extra color bands are just an extended form of the 3 band system so you could have a “brown, black brown brown” resistor, which would just be 101 Ohms. The color band’s location is an identifier:

Resistor showing some common color code markings

Resistor showing some common color code markings



color 1st band 2nd band third band
Black 0 0 x1
Brown 1 1 x10
Red 2 2 x100
Orange 3 3 x1000
Yellow 4 4 x10,000
Green 5 5 x100,000
Blue 6 6 x1,000,000
Violet 7 7 x10,000,000
Grey 8 8 x100,000,000
White 9 9 x1,000,000,000

Sometimes Gold or silver are seen in the third position, these resistors are less than 10 ohms.
Gold is a “divide by 10” and silver is a “divide by 100”.
So a “Brown Black Gold” resistor is 1 ohm, a brown black silver is 0.1 ohm. Not common outside of equipment running multiple bipolar transistors in parallel.

Older resistors (dog bone) and some tubular composition resistors of that same era followed the number to color ratio, but differed a little bit as to which way they were to be interpretted as the body color was first digit, one end was dipped in a color for the second digit and the third digit (multiplier) was a spot in about the middle of the body.

Tolerances were/are either
No marks on the end of the body (old) meant plus or minus 20 percent
Silver band meant/means 10 percent
Gold meant/means 5 percent
If you find some older aerospace equipment you might see a red band which meant/means 2 percent.
these tolerence color bands are still consistent with today, but you also have
Brown as 1%
Green is 0.5%
Blue is 0.25%
violet is 0.1%
grey is 0.05%
This is to reflect the improved quality control, materials consistency and processing of products for various fields where extreme accuracy is desired.

Tolerances are deviation from the “target” value meaning plus or minus that color band identification for accuracy- if the actual measured resistance varies from the indicated value more than the tolerance bands indicate, (and everything including test equipment is in calibration and the resistor is the only thing being measured), the resistor has shifted in value, and depending on where in the circuit it is located- replacement is the likely best course of action in most cases.

Resistors in series are additive in their resistances. This also creates a situation where they act as a voltage divider. Which just means if you measure the voltage between 2- 100 Ohm resistors across a battery or other voltage source, the voltage measured at the midpoint will be half the total voltage applied across the 2 resistors in series. and voltage is proportional to the resistances of a voltage divider. So if you replace one 100 ohm resistor with 2-50 ohm resistors, The voltage between the two 50 ohm resistors will be 1/4 (or 3/4 depending on the common reference point of the meter lead) the applied voltage. And between the 50 ohm and 100 ohm resistor, the voltage will be half. (providing one test lead is kept on the same point of reference of one of the applied voltage terminals. (like the negative pole of a battery.)

Resistors as voltage dividers

Resistors as voltage dividers

Now if you build your circuit so that center point of measured potentials is arbitrarily decided upon for an audio ground, voltages that measured between that arbitrary ground and the negative supply are negative with respect to that audio ground. It is a way of “floating” a circuit, say a low power audio preamp IC, or op amp chip. As long as the audio ground is kept separate from the negative side of the power source, the IC should function. This was a trick used in many audio amplifiers that ran PNP and NPN complementary pair transistors in the output stages (transistors will be discussed later) from a “single ended supply”. I will cover this more with some of the other components as it applies to their sampe circuit.

When resistors are in parallel, their combined resistance is defined and calculated by the following formula:

Resistors in parallel

Resistors in parallel

When the resistors are in parallel, they have the same potential across them, but the current flow will be divided proportionally between them. If 2- 100 Ohm resistors are in parallel, their combined resistance is 50 Ohms. When resistances are in parallel, the power rating is effectively doubled if they are the same value of resistance. This is not true if they differ in resistance, it will effectively be the power rating of the lower resistance component.

Now, if you measure resistance of a component and you happen to have the leads in contact with your fingers, your resistance measurement will be off because you are effectively a parallel resistor in this example. You can hold the leads of your Ohmeter in your hands safely, and you can measure the resistance of your body, or the resistance of just your finger, or portion of it- this is how some of the early “Lie Detector’s” worked- the theory being if you were telling a lie, your body would respond by sweating and thus lowering your inherant resistance. This is why your measurements may be off if you are holding a component with both hands.

Again, I try not to use jargon as it gets in the way many times, and too: many people get lost in the minutae of jargon and see that jargon as important and fail to see the bigger picture when they just focused on the jargon alone. People also tend get lost in math, so I try to only include that aspect when it is needed.

It is important to note that regular carbon composition resistors are not generally considered as high of a quality resistor as the film type resistors made from carbon and metal film. If the composition resistors get hot enough to discolor the paint of the bands, the value is likely to shift, but the film types and wire types are more stable in that extreme circumstance. This is because heated materials generally expand, and the resistors are no different in this respect, but it is this expansion that can make them noisy at times because the carbon composition may get distorted under heat and thus not remain as compacted as it was before it was heated, thus shifting value and potentially introducing noise. The wire wound types of resistors usually do have an “inductance”, and they are not suitable in some applications because of that, but most heavy duty power resistors will be wirewound types. Most film resistors these days are also more flame resistant than older types or the older composition types. While not common, they (non flame retardant types) can burst into flame which can ignite combustible materials that are close by.

There are also some power resistors which are “fusible”, which simply means they can also act as a fuse if current draw gets excessive. These are not always marked but usually are made from a “cementitious” material. (they look like concrete). Older wire wound resistors are common in tube radios and resembles a terminal strip attached to the chassis, but under that folded metal jacket is the wire wound resistor with various resistance taps. These are most often found in the “B supply” of tube equipment, and if you have one that has a burned out section, if you have the schematic, you can simply bridge the burned out section with a 10 watt cementitious power resistor of the resistance indicated in the schematic. When these burn out, some tubes lose their “B” voltage, and the remaining tubes sometimes see a higher than normal B voltage on the plates, and some none at all(if you are checking voltages on first power up.). Other equipment that may need repair of their “B Resistor” that have them, may have a higher power requirement for any repair substitution, but in that case it becomes a case by case solution.

If you are working on vintage audio, check the composition resistors- if they have drifted in value, they can become noisy and need to be replaced if you want good accurate audio reproduction. The original composition types can become noisy, which is why some purist insist on replacing them all regardless of condition, which is certainly an option, but if you look at the investment in time, it may not be recoverable if you plan to sell the unit. Yet at the same time replacing composition resistors simply because they are there becomes a subjective topic in itself. No question resistors have gotten better over the years, but the resistor manufacturers then, as today, put out a quality product. If the composition resistors have not been heated beyond their expected design parameters, their value should not shift any more than a few percentage points at most and they should remain quiet. If they have been overheated, or have become microphonic- certainly replace them. It really becomes a matter of originality of the equipment versus the modern reliability or trying to “fix” something before it breaks or even becomes a problem. It is one thing to replace all of the composition resistors if several have proven to be noisy or vulnerable to noise. It is quite another to simply replace them all simply because they are composition resistors. It becomes a matter of personal choice, and there are people who will never believe a composition resistor can remain quiet if it has not been abused and will go ahead and replace all of them anyway. And with audio, many people are willing to throw thousands of dollars at things to solve issues that may or may not be real as it is. The power of suggestion is massive when it comes to audio. If a person believes something will “fix” an audio issue- real or imagined, measurable or not- there will be those who spend countless thousands of dollars following that belief.

Over the years, I have dismantled many things, and the real proving grounds for “quiet” and “Low Noise” was and still is the aerospace industry. Composition resistors were used well into the 1980’s, in part due to US Federal Law dictating US sourced parts used in military equipment (which exists no longer), but at that time they were very good quality, and still are today, but they have their reputation following them regardless. Metal and carbon film resistors date back to the earliest days of transistorized radios made in Japan and they were and still are good. So the reality is only in part a subjective one when it comes to audio as to which is ultimately “better” film versus comp, but in most cases when doing repairs or building things these days, the film resistors are more prevalent and cheaper in price than the composition types. So if you encounter some equipment with composition resistors, it is a case by case basis to determine if the composition resistors need to replaced.

As this pertains to the area of alternative energy systems, you will need resistors to build things: if all you have are used units from scrap boards, there should be little issue with used pieces, and you can test them individually with an Ohmeter to be sure they are okay. If you build from new stock parts, the film resistors are among the cheapest ones available these days so it becomes difficult to not use them. However if all you have is composition resistors salvaged from scrap boards- do not be afraid to use them if you have checked them for accuracy.

The bottom line is simple- use what works consistently for you. While resistors are durable and quite reliable, they are not indestructable. If you encounter some that have failed, they can be an indicator that something else is wrong. If nothing has failed, and the system works fine, and within the performance measurements of a new unit- you do not need to assume the composition resistors just have to make noise and they therefore must be replaced, for to do so means you like to throw money at things, and it may really be a situation where it does not fix anything because nothing was broken.

There are also light sensitive resistors (Photo resistors), some of the uses are as a flame sensor in an oil burning furnace, the tremelo section of Gibson Mercury guitar amps, light sensors for street lights and house lights, some optoisolators that use an incandescant light inside the chip body have a photoresistor as well. And where they are in a circuit will allow you to determine if there is a current limiting aspect for the resistance in the circuit, or a voltage dividing character, or for coupling of stages. A photoresistor can be modulated for audio effects as in the Gibson Mercury, or it can be used to establish a threshhold for triggering a switch such as the light sensors. However photoresistors can drift in value over time just as Thermistors, and even though they are considered passive devices, their response range may drift as well.


an old house renovation blog

The main blog.
the begining point place to start

The tangential blog.

The passive solar blog- outgrowth from some projects of mine.

Posted in Alternative Energy Circuits, Alternative Energy Circuits for "Homebrew", Audio Amplifier, Back to Basics, Basics, Uncategorized | Tagged , , , , , , , , , , , , , ,

Gain versus Power

The topic of amplifier power is often argued about, but not really understood by many of those who would argue about it. The truth is simple- most audio amplifiers are going to sound about the same at normal listening levels because at normal listening levels, you are hard pressed to send a signal of 10 Watts to the speakers in most cases for normal listening levels unless you happen to have some very inefficient speakers. And there are Grateful Dead fans out there that just turn the volume all the way up to listen to the song cuts. But there are several inter-related concepts here. 1) is efficiency of the speaker- more efficient speakers require less power to drive them to certain sound pressure levels. 2) gain of the power amplifier- most are going to be about the same gain factor referenced from the line level input. 3) the type of amplifier- Class D, Class C, Class B or Class A.

Some will think this is dismissive of amplifier power- quite the contrary. A larger amp will handle low frequency power demands better than a smaller power amp when the amplifiers are seeing complex audio dynamics or sustained low frequency signals at elevated output levels. A larger power amp will also present more clarity of high frequencies- or “definition” at higher volume levels in many cases as well. But does more power guarantee more sound pressure levels? The simple answer: No. What is needed is gain to push the peak voltage swings as close to the “rails” as possible without pushing to the rails. What this simply means is the power supply and the various voltage divider networks in the system establish the upper and lower limits of the voltage swing and current available. When you read the datasheets on the various audio op amps (generic term for operational amplifiers used in audio, video, instrumentation, etc) available, they will talk about “rail to rail” voltage swings, (and this applies to the power “rails” supplying power to the Op Amp, but internally, the Op Amp also has voltage divers and regulators that establish internal power rails as well). This just means that the input signals can be amplified ultimately up to the voltage rails. If your signal gain pushes the op amp or any amplifier stage to the point where the signal peaks hit that rail- clipping occurs. In otherwords, too much gain in one stage with an adequate input signal will push the resulting signal in that next stage to the point where the peak amplitude would exceed the voltage rails in a perfect amplifier stage, but because the circuit has limited voltage range, anything that would exceed that power rail only can reach the power rail and not go beyond- the result is a signal with the tops cut off. While useful in some guitar effects, it can present some issues for systems with marginal speakers if they are driven too hard.

To illustrate this, I refer to a recent project where one 30 Watt per channel (Class D) was compared head to head with a 100 Watt per channel (Class D)amplifier. The first one was for an initial prototype, and it was loud at full volume- however the second one had a higher power rating (peak), but had the same gain factor as the first. Both were just as loud as each other at full volume, but the larger had a certain degree of better definition or clarity. They were not “loud enough” for the application, so an extra gain stage/voltage amplifier to achieve higher sound pressure levels. So- as far as sound pressure levels are concerned- for 2 similar power amplifiers of different wattage ratings- the extra power did not translate to higher sound pressure levels because they were essentially the same gain factor relative to the line level input. When dealing with amplifiers that are generally available commercially (ie, from a store), this ia a generally true statement.

Preamps were added to the project systems, the final version of the preamp was a simple gain factor of 20. In other words 50 millivolts in gave 1 volt output. In this location in the circuit it is essentially a simple voltage amplifier. This was where the power amplifier differences were truly heard. Both the 30 Watt system and 100 Watt (both are per channel) had the same gain with the same gain in the preamps, but the higher power amps were less stressed with the higher gain input at elevated listening levels and thus had more clarity. (now there some differences in the “front end” of these amps in part some of the features, but also general construction. However the simple voltage amplifier section I built and added was a real game changer when it came ot sound pressure levels because that gain made the 30 Watt amplifier louder than the 100 watt amplifier (without amplifier stage) with just the mere gain factor of 20 added at the input before the same gain preamps were added to the larger amps. The 30 Watt amplifier could achieve sound pressure levels higher than the 100 Watt amplifier (without that gain stage) at midpoint of the volume control on the 30 Watt amplifier and the 100 Watt amplifier at full volume. The same models of speakers were used for both units- but gain made the real difference in performance in terms of initial analysis. When the gain stage was added to the 100 Watt amplifier, the sound pressure levels became comparable again, but the clarity of output went in favor of the larger amplifier as one would expect. However the differences were slight enough that you really had to listen carefully.

Conceptually power and gain are similar, but they are not the same. Most solid state power amps are going to have about the same gain factor from the “Auxillary Input” to the output to the speakers. It just “is” that way when dealing with home and mobile audio. By the same token, adding a gain stage to the input will yield higher sound pressure levels to any amplifier. But the bottom line is this- the amount of measurable signal gain from the line level input of a Harmon Kardon 730 is going to be fundamentally the same amount of gain from the line level input of a Marantz 2040, or Pioneer SX1010. At normal listening levels for most people- they would be hard pressed to accurately identify any differences between those amps, and most could not (regardless of their claims). You would only start to notice differences at higher than normal volume levels, and I have had all three of those models and while noise floor and THD ratings are close among the 3, as long as you were not loading the amplifier’s power supply sections excessively, they were comparable on clarity. As far as sound pressure levels at full volume, which is not a wise thing to do, differences were not as great as people might think because they had similar gain factor. Now, age, condition of components, and environment can affect the results, so if someone tries to replicate this, they may get different results, but they will not be as significant as they might think. Personal biases come into play here and subjective judgements can vary between 2 people of similar backgrounds.

How that output power is measured also plays a role. Most of the modern high powered audio for home or automotive use commercially available is just simply a peak rating, which is why you can get 2000 Watts out of an amplifier fed by #6 gauge wire (if you are lucky and not have it lighter gauge). 2000 Watts will melt the insulation off of 6 gauge wire if it were an RMS rating or continuous on 12 volts nominal supply. The fuse is another thing- 30 Amps on 12 volts- 360 Watts. Nowhere near 2000 Watts continuous. These power ratings also do not accurately reflect the amount of gain you have.

Don’t get me wrong- there are some legitimate booster amps that are fed by “00” welding cable, but most of those are custom made, and take up some real estate in a truck bed. But whether they are 1500 Watts or 2000 Watts, they will have roughly the same gain factor when used as booster amps when looking at voltage/potential “gain”, but when you are limited to 12 volts or 24 volts, power is derived from current flow- not from increased potential/voltage. The booster amps being a variant of AB and B types of topology, will also draw a lot more current than “Class D” amps, so they will have the potential to generate more significant sound pressure levels, and will have legitimate RMS values for that power rating, but at a cost in terms of current draw and volume. Booster amps can be made from Bipolar transistors or MOSFETs, the Class D amplifiers will invariably be MOSFET finals. Booster amps for automotive applications are a little different breed of amplifier than the usually thought of “Power Amplifier”, in large part because it is not so much signal gain as it is current “gain”, though some can be designed with voltage gain into them, but it is actual current flow gains that are seen at the speaker terminals to produce the overall power ratings, if even only instaneous. Most of the well made speakers used for automotive “subs” actually have a significant amount of copper wire of a larger wire gauge size on the speaker voice coil form- usually much more than most home audio speakers- this is due to that higher current of the audio output in mobile audio. This is a different set of factors for consideration of amplifier gain and booster amps are a different animal than what I described above in the compairison, which essentially is just compairing two similar power amp topologies (class D”) compairing two amps designed for home or automotive use with enough gain to be able to produce adequate sound pressure levels from the output of an MP3 player.

Some may be confused by this, some will argue vehemently about some aspects of the discussion, but the reality is that when you add gain to a system- you will make it louder in terms of real sound pressure levels regardless of the power rating or topology of the amplifier. Power does not always equate to the amount of gain factor of any amplifier- but at the heart of it though, a higher power amplifier will usually produce more clarity at high sound pressure levels when the amount of signal gain is otherwise equal, and this would be the only legitimate reason to favor higher power amplifiers, but at normal listening levels- the actual amount of power needed is lower than many people think, and the environmental variables for any given space will also dictate where that point will be. The problem though is that of perception- it is a very subjective thing and also highly influenced by prejudices, backgound and most importantly expectation.

If you expect to hear a difference when you change something in an audio system- most of the time you will– but is it real? This is why many people will argue my points I bring up here. Now don’t get me wrong- we all listen for different things, different qualities to the audio. I am not immediately dismissive of those who would make claims that some might think are extreme- after all, if you remember those “3D posters” that were all the rage in the 1990’s- I never saw anything but squiggly lines, many people saw the images that were supposedly there- are they wrong? No, Am I wrong? No. Our brains just processed the incoming information differently. Can people hear audio tones above 20,000Hz? Most cannot- but here is the important detail- While the highest note on a piano is well below 15,000Hz, it is the undertones, overtones, resonances of materials that all come together that allow you to distinguish between a single Bag pipe drone, a piano key, a harp, a harpsichord, trumpet- etc. And many of those tonal qualities are present above your normal range of hearing- and they are very real- but doctors will say you cannot hear them because they are outside of your range of hearing. And so they are- but yet they color the notes that you do hear.

Thing is- people who repair and tune pipe organs can usually identify which organ is being played- it’s location: because of how they sound, their sound quality and other little details of subtlty are what make each pipe organ very unique. I may have mentioned this before- but these specific individuals are listening for something you don’t normally listen for. For most people, all pipe organs sound alike- but they are not the same.

Plus there are some other factors in this equation of sound as well, speakers used, construction of the speaker, the enclosure, the crossover point, the audio content, etc, will influence sound pressure levels as well, so while someone may have a high power amplifier and can “make it loud” by turning up the volume, it does not mean as much as they think it does because high sound pressure levels are not normal listening levels for most people.

Lastly- if you were standing in front of a set of speakers that were 100 percent efficient at converting the energy from the amplifier to actual audio power and the air were also 100 percent efficient, standing say a meter away- a mere 1000 Watts is all that is needed to turn your body into water vapor instantly.


an old house renovation blog

The main blog.
the begining point place to start

The tangential blog.

The passive solar blog- outgrowth from some projects of mine.

Posted in Advanced, Amplifier Gain, Audio Amplifier, Basics, Uncategorized | Tagged , , , , , , , , , , , , , , ,

Troubleshooting- part 1


A few caveats with audio and RF amplifiers:
1- Never operate an amplifier without a load. To do so means the amplifiying device must disipate the energy, or the output transformer has to disipate that power, and many will fail in milliseconds. It is never good.
2- Line voltages and B voltages can kill. When a circuit is plugged in- whether live or not- use one hand in the circuit only and make sure your body is not in contact with anything conductive.
3- If using junk speakers, keep controls at mid level and volume down.

Now, many people have different opinons on what “servicing” an audio amp entails. For some, this means essentially totally rebuilding the amp, for others, it can mean replacing just what needs to be replaced to make the amp operate within expectations, much as it means for your car or in the past with TV sets. If you are doing this for money, you need to discuss with the amp’s, or device’s owner just what it is they want. And if some snobs want to be ciritcal of the lesser definition- that is their problem for being unrealistic in a real society. If the snobs want to rebuild the item with new film resistors, new electrolytic capacitors, and replacing ceramic disk caps with polyester or other film type, new low noise transistors, low noise op amps, etc, this is beyond “normal” servicing and constitutes totally rebuilding the unit- but they cannot call it that because they are usually reusing the original controls. If someone is expecting that level of work to qualify it only as being “serviced”- they tend to be the first ones whining when they get their repair bill for their vehicle- especially if the service station were to use their definition of “servicing” applied to their automobile.

If someone wants to do that much work to a vintage amp they typically should already know what is involved, why they are doing it and many would certainly not being paying someone else to do it for them as they could do the work competently themself. It is simple economics to not do that level of rebuilding to try and sell it, but some try.

When I do a repair, I clarify what it is that person wants. Because one can invest the equivalent of a thousand dollars or more in parts and time on many amps with the end result of the amp not being salable because it’s street value is just not there even with the 4 amps considered the “creme de la creme” of solid state amps. Especially if one takes the extreme definition of “servicing” an amp. When I have seen those types of whiny ads posted on Craig’s List and elsewhere, I usually know who it is (of a group of about 3 people) and they are trying belittle everyone else to try generate business for themself because they cannot sell the amps they have because they sank too much time and materials into them and no matter how much 1950’s era “salesmanship” they apply- people are not buying the amps. I spoke to one earlier this year thinking he had some potential need to fill in some lower price points so he could appeal to more people and generate business for himself. Instead he was trying to sell me on amps he had worked on already and put too much into them as if I just floated down on a big white balloon and knew nothing of electronics.

Now it does make sense to replace the filter capacitors in older equipment, but if that is all you do, or reconfigure a tube amp from an autobias type to one where you set individual biases, neither one constitutes “recapping” or “servicing”, but there are some people out there who do sell that small amount of work as “Service”.

Sometimes capacitors do not need replacement unless you are wanting to change the “type” of coupling capacitors. Mylar capacitors have been around since the 1950’s, paper caps on the other hand have been around from the early days of radio- some have one preference of one over the other. Some people want “Paper in Oil” types, (which is another type from the 1950’s adapted from other oil bath and other paper types that date to the 20’s). “polyester” and “Mylar” is the same material- Mylar is just a trademarked name of Dupont and nothing more than that. However, Polyester is a different material than Styrene, or polystyrene, which is a little more modern with it’s own audio characteristics. Many people can hear no difference between the dielectric types, yet some can- many times that difference is very subtle, just like the differences between Coke, Pepsi and RC colas. Not everyone can taste the difference, but some of us can. With audio caps it is no different. But if you take the time to compare them, and listen for clarity, listen for bass reproduction and detail, listen for treble tones- are they clear, or are they harsh, or are they “mushy”? Think of it like tasting wines. The first two wines I sampled many years ago, my uncle was disappointed because they were in theory two diffferent wines, but largely the same grapes were used for both- yet I could taste no discernable difference because I had no preconcieved notions, and the two wines were not significantly different as both were “varietals”, but this is not to say I could not distinguish them from other wines even then, the fact is I can. It is just that some wines you need to surpass a certain cost per bottle to really start tasting differences. The same is true with bourbon, the same with vodka, the same with scotch whiskey. If you go in with preconcieved notions, you have an expectation and the result is usually a self fulfilling prophecy, and therefore not accurate. Just because you cannot hear any difference however, does not mean it is not there. But there is the matter too of expectation, which can lead many people to invest in a lot of materials that really may not be doing what they owner thinks they are doing.

So, once I clarify what someone wants done on the radio or amp, or other device, it is straight forward from there. Sometimes an amp or reciever only needs controls cleaned- some do not see that as “servicing”, and as long as you do not present that as “servicing”, you will not have any misunderstandings. But you still do have time invested in that amp doing that work to make sure it was functional to a minimum level. Most of the people actively advertising for “Pioneer” and “Kenwood” equipment are only looking for the top end units and are only wanting to pay about 10 bucks for the amp if they find it, and they will dismiss anyone else’s time that may have been spent on the amp cleaning it up, locating parts, etc. I will not deal with those people when I do come across those amps because I know how they are, and I have other people to sell to.

If the amp is quiet, (turning up the volume with no input signal reveals the “Noise Floor” of the amp. If it is quiet- in that hiss is not noticed, such as a vintage Sherwood I have, the amp may not need much attention, but if there is a great deal of noise, then you want to look into things much further, such as checking transistors for poor solder connections, poor general condition of certain transistors and electrolytic capacitors (ie leaky) or bad solder joints on the circuit board or chassis, or dirty tube sockets, defective tubes, noisy composition resistors or dirty controls and switches, and checking idle current draw with zero signal on tubes and transistor units, etc. The procedures vary between tube and solid state for setting or testing idle currents and for right now I do not plan on going into much detail on that aspect anytime soon, later it may become a post though.

If at normal listening levels, if the audio signal is distorted, then you need to decide a course of action- replace all transistors? Replace just the leaky/noisy ones? Or if tubes, find the weak ones or misbalanced or otherwise defective tubes. If microphonics are a problem, which is a situation where physical bumps to the floor in the room or amp result in a corresponding noise through the amp. It is not uncommon for headphones to reveal microphonics before you hear it through speakers, and many vintage solid state systems with PNP type transistors suffer from noisy finals. Microphonics can come from a loose grid wire in tubes, to failing connections in transistors, electrolytic capacitors or resistors not being as tight as they were when new, etc. Even disc capacitors can become microphonic due to internal delamination or leads pulling loose.

This is where actual troubleshooting begins.

Integrated circuits can pose their own problems- avaiability is one of them moreso in tuners and tuning sections of recievers than elsewhere in the system. (An integrated amplifier, or amplifier has a separate radio tuner outside of the amplifier. A “Reciever” has that tuning section integral in or on the amplifier chassis) Audio preamp ICs are constantly improving and somewhat interchangable, with the most common one: “4558” which is a design dating from the 1970’s and is still in use today in many amps and still in production. While it is dual op amp chip based on the single channel “741”, it is much quieter the 741 and the 1458 is nothing more than a dual 741. However, over the years there have been several improvements by other manufacturers that are even quieter and bear different part numbers. For example, in the late 1970’s National intorduced the LM387 dual preamp. Great amp for phono preamps ( and I made a few back in the 1980’s with great results) which was made to capture the tape deck preamp market based on how simple the tape preamp with “NAB” equalization was in it’s design. It is designed primarily as a “single ended” amplifier (one power supply), but has not been in production for almost a decade now. The vast majority of modern preamps are a “dual supply” or “Double ended” supply, which is how most solid state audio amps are made. There is nothing wrong with a “dual ended supply”, but it does become an issue when dealing with low voltage systems such as in automotive applications.

There are some other common “FET” or “BiFET” op amps, such as the LF353, TL082, TL072, and some others. Most are still made today, and the LF353 and TL072 make some reasonable quality utility preamps and can be used in any circuit that has a 1458 or 4558, and the TL081/TL071 can be used with the “741” circuits that were in many guitar circuit construction books from the 1970’s onward. The TL7x series of op amps are lower noise than the TL08x series. Plus most of the FET and BiFet op amps are quieter in general than the 741, 1458 and 4558.

The 4558, 741 and 1458 had many prefix letters, but they are the same ICs for numerical type regardless of who’e prefix is on them. Today there are some low voltage preamp chips/op amps that can be used on 12 volt audio, but they need to be handled differently as they are dual supply types which complicate things as the audio ground cannot be the same as the chassis ground. Some newer op amps too are low enough in noise to be used for radiation detectors, which makes them quiet enough for the most discerning phono preamp circuits. That is a topic for later discussions

Servicing a tube amp that has not been use for years usually entails replacing electrolytic capacitors, checking resistors in the power supply with some potential replacements for those damaged or out of value, testing the tubes and replacing weak or defective tubes, replacing defective tube sockets, input jacks and terminals, checking idle current, cleaning controls, switch contacts and tube sockets, and confirming the amp is quiet. Replacing all audio coupling caps, and comp resistors is a case by case situation depending on the preferences of the owner. And if the amp is to be sold- replacement of all of those parts is a waste of time and money because doing so puts prices in the stratosphere well above “Street Value”, and if the amp already has polyester capacitors- these are the most reliable types in use, and have good sonics.

Now for amps and electronics in general, the basics for troubleshooting are:
First step, especially if the item has come to you and you know little of it’s condition, the obvious things are the first order of business- checking the power cord and visible wiring for damage. Essentially checking the first obvious things if there is some evidence of damage from mishandling. Sometimes an issue arises at the wall plug where the insulation is pulling away from the plug leaving conductors exposed. Close inspection usually reveals some tearing of the insulation and expose wire conductors. If the cord is in good condition otherwise, replacing the plug end with new one will suffice. If the cord is in fragile condition- just replace the whole cord.

Second order of business is cleaning controls and switches. This is not a hard thing to do, it usually entails simply the application of a contact cleaner, or LPS-1 into the gap of a potentiometer where the terminals come out, or the “rotation stop” stamped into the cover. Some controls use a resistance wire, and contact cleaner will work, but is sometimes not needed. LPS-1 is a lightweight lubricant with some solvent action and is not conductive. Contact cleaner can be conductive if it is water based, sometimes older cans of cleaner used a CFC- which are effective and have a distinctive odor, and some are a petroleum solvent base. The label will tell you directly or indirectly what is in it. Depending on the materials used, you need to use plastic compatable chemicals.

Often you will see people suggesting a product called “Deoxit” produced by Caig. This has it’s uses, but not in potentiomenters and absolutely not in slide pots as this softens the substrate that the carbon track is applied to and will destroy those. Now if you dismantle the control and only apply it only to the metal contacts, that is a different story, but that is usually more work than it is worth. If Deoxit is applied sparingly to the exposed contacts of a switch, you will be fine. Some rotary switches have a different issue in that a vinyl plastic was/is used to hold the center contact that is rotated through the positions- these often fail just from age and fall apart, so are best handled with as much care as you would a “Ukranian Easter” egg that is several years old. Even then though, the Ukranian egg will be more durable. If you have one of these switches and it is already broken, but the pieces are all there, then you need to draw out the schematic of the switch contacts and in what position the center portion makes it’s contacts and then find a modern or vintage bakelite type that can be wired to work in that location. Bakelite is also known more generically as “Phenolic”.

Once those steps are done, then a physical inspection of the chassis is in order. If the power cord was replaced because it was a natural rubber insulated type that hardened, you may find wiring inside that is in the same condtion or worse. If mice got into the unit, that is nothing short of a minor disaster if you do not have a schematic or cannot identify the chassis. Mice will chew on everything, plus leave a corrosive mess behind. When dealing with newer electronics that utilize an IC, locating an “Application Note” or “Data Sheet” for that IC will give you a good idea of what the rest of the circuit around it is. At a minimum you can identify the voltage pins and inputs and outputs.

If the unit is solid state, if older than about 10 years, replacing the filter caps in the main power supply is usually a real good idea before applying any power, and these rarely “reform” (explained later). The same if you are working on an older 5 tube radio- most of those filter caps dry out. If plugged in and left that way, it is fire hazard. Older collectible audio gear and other older radios that have a metal can capacitor should be checked at where the leads come out of the capacitor- any evidence of corrosion, soot or leakeage from inside means replacement is your only course of action.

If the leads or terminals of a “can type” of capacitor “look” clean, you might consider bringing up power on the unit with a “Variac”, which is a transformer that allows you to dial up the applied voltage. Begin at 50 to 60 volts for an hour, and then increase 10 – 20 volt increments (after the first hour at the low voltage) every 40 minutes to an hour. Doing this reforms the oxide layer on the capacitor plates to increase the insulation factor between capacitor plates. This works about 40 to 60 percent of the time, and can be worthwhile to at least try it. You can gut that capacitor out later and stuff new ones in if the capacitor does not reform and you want to retain the original look, or solder a terminal strip on the underside when possible and install the single unit capacitors under the chassis. Some chassis’ are close toleranced, such as under a Sherwood S5000 series audio amplifier, and the only real option is to gut that capacitor that is held with a clip located at an angle to the chassis- gut it and stuff the new component capacitors inside it after wrapping them with a high quality electrical tape or shrink tube, and these is barely enough room under the chassis for careful placement of the other electrolytic capacitor values.

What happens if you have a capacitor that does not reform the oxide layer is the capacitor shorts out and overloads the rectifier tube and potentially burns out the “B voltage” winding of the power transformer if left on long enough. The transformer in that situation gets hot enough to melt out any wax that was in it, and the older radios from the 1920’s into the 1930’s were often potted in asphalt/tar. If in your initial look at the underside of the chassis, if you have a transformer that has leaked out the asphalt potting, or a great deal of wax, don’t even try to reform the filter caps as they are likely shorted out already. The chances of a transformer surviving getting that hot are exceedingly slim (you have better luck betting on 99:1 horses at the horse racing tracks.)

If you isolate the transformer leads from the radio when you suspect a shorted transformer, you can check the transformer by plugging it into the wall for short periods as you check to see what each winding pair shows for an AC voltage. If any are significantly lower than they should be, such as seeing only 3 volts on a 12 or 6 volt heater winding, the transformer is likely junk. The transformer will usually also get hot quickly. 60 volts on a winding that should be 250 volts is definitely an indication the transformer has a problem and likely is junk.
Even if it seems the filter capacitor(s) have reformed, check the transformer for heat. In normal operation that transformer can get warm, but only warm enough that you can keep your hand on the transformer covering bell. Also check the can capacitors to make sure they are not heating up. Sometimes they will feel like something is boiling inside of them, which on a case by case basis, should be monitored, but at any indication of excsseive current flow in the form of heat- replace that capacitor.

If you replace the filter caps- make note of the can polarity and any isolating hardware, washers, phenolic mounting plates, etc. There were some can caps that had a common positive can. If in doubt, look at the schematic to make sure. If you are looking at some European gear, sometimes it is not entirely clear what the polarity is of the orignal capacitor, and you need to rely on the schematic.

If the transformer looked okay and nothing looked melted or burned (some paper capacitors will look a bit melted, but that is normal for many of that type. If however the wax is visibly very much melted out of the paper or ceramic jacketed coupling capacitor, it should be replaced. More on these later.

When reforming is attempted, monitor the transformer for excessive heat. A “warm” transformer, one that you can rest your fingers on for an extended period of time, is usually okay. But watch for any tubes showing redness on the outside tube structure, or purple glow within the tube. These are indications of a problem- if the outer structure of the tube turns a dull red or brighter- that means the filter capacitors are junk, or something else has shorted on the output circuit of that tube. If the tube develops a glow inside- unless it is a mercury rectfier or gas rectifier which are supposed to glow, that is an indication of gas ionizing inside of the tube. Some power amplifier tubes will show a tiny amount of blue in the vicinity of the heaters or plates, this is something to be watchful of, but not an automatic condemnation of the tube or capacitors unless it becomes a glow that fully engulfs the tube envelope.

If the tubes light up okay, then you can proceed to some other basic tests if it is not functioning.

With Solid State gear/radios, look for electrolytic capacitors that may have vented, or may have leaked. If they are bulging or there is a smoke residue on the PC boards, or just two leads poking out of the PC board (indicating the body of the capacitor is somewhere else), or they show a black or dark brown substance on the top of the capacitor- just replace the capacitor(s) and those that are around it. Much of the solid state electronics made from the 1950’s onward have cemented the capacitors to the circuit board and they were made that way so they would survive the vibrations of shipping from Asia or Europe and remain bonded to the PC board. If the stuff looks thick and rubbery like contact cement, it is just adhesive. If it is crumbly, it is likely from the inside of the capacitor nearby. That adhesive can be corrosive, so if one capacitor shows corroded leads from being in contact with that adhesive, just replace all of those that were cemented. If you are just wanting to do some functionality tests, plug it into the variac and bring up power over the span of a minute to reach full power and watch the meter on the variac the entire time- if it shows excessive current, which is anything more than about 20% of it’s power rating on the device’s label(once you work on a few things, you develop a “feel” for where to draw that line, and not everyone is going to agree on where to draw that line, but anytime the unit draws more power than it’s label indicates, then you have a problem), the filter caps are bad typically, but there may be other problems as well.

If you do not have a variac, then simply take a lamp, wire an outlet so the lamp is in series with the bulb, and then use an incandescant lightbulb (or do this in steps) 75 to 100 watts in size to see how relatively bright it gets. A Solid State stereo for example will marginally operate with a 75 Watt bulb or 100 Watt bulb, but if the bulb lights to normal intensity, just shut it down as the amp has something shorting. The lightbulb in this case limits the amount of current able to flow through the amp or radio thus minimizing further damage. It is essentially the same thing as old appliance testers.

Dim Bulb/Appliance tester

Dim Bulb/Appliance tester

Many of these following tests can be done with a solid state amp on a dim bulb tester with a smaller bulb (if you get some audio activity you may not have that many issues in the amp), but until you know nothing is seriously wrong keep it on reduced power then go forward from there. A tube amp may or may not begin responding audibly with a dim bulb tester, but the tube amp is a bit simpler in general construction and therefore easier to troubleshoot without being under power.

If the unit passes the dim bulb test. and if things appear normal visibly, but the unit does not operate, you can do “noise injection” on units where one channel may be defective or if you know the finals are fully functional. Noise injection is just using an insulated (plastic handled) screwdriver and touch each grid terminal of tube amps and tube radios, or the base and collector terminals of each transistor in solid state radios and amps starting at the output, and work your way back. Where the “buzz” fails to appear is usually the area where a problem exists- such as a “coupling capacitor” that has pulled apart internally leading to an “Open” capacitor in tube equipment, or a transitor has failed in solid state gear.

Paper capacitors and some other material coupling capacitors indicate the outside foil layer with a “-” sign or band or special dimple if US made. These can be replaced with “Stacked film”, “Polyester”/”Mylar”, “Paper in Oil” (PIO), “metalized film”, “Ceramic disk”, etc. Many of these do not indicate an outer foil, but if you can identify what lead attaches to which side of the “Stack”, or “Disk”, you can place the capacitor in a manner where that one side that would be the “Outer foil” of the original capacitor is now the side facing away from the chassis, and you can use the chassis to act as the other part of that shield. I have in some rare instances actually replaced paper capacitors with high quality ceramic disks, and in doing this I still had acceptable results, but I much prefer the stacked polyester types or wound polyester or styrene types.

With solid state gear, the problems can be more than just a failed capacitor. Transistors themselves can become noisy as can any type of capacitor. Integrated circuits and composition resistors can become noisy as well.



Another problem area with tube era gear and some older solid state gear are the composition resistors used. The old “Dog bone” resistors are the least stable and often drift off value are primarily found in pre World War 2 radios, though some early film types used a similar construction (largely Japanese origined radios and European radios, but should not be confused with the older composition dogbone type). Newer composition resistors can also drift in value, and in some cases both of these can be fire hazards. When they just drift off value, this can affect sensitivity of a radio, or lead to inconsistency between two channels of a stereo. In tube gear, you can usually measure the resistors without much interaction from other components when the unit is off and removed from power due to tubes not conducting when not energized to see if the resistors deviate much from their color coding. Transistors on the other hand are different and direct measurement of resistorswithout removing at least one lead of the resistor is at best a gamble. However if you are measuring the relative resistance between the 2 channels of a stereo that has one working channel and one faulty channel, that is a different story if you are compairing resistance between identical points of each channel. But noise or signal injection are probably going to be the fastest way to narrow the area down by compairing the corresponding devices found between the two channels. In the event you cannot generate noise in the output of a solid state unit, you can signal trace with an audio source such as the audio output of a signal generator, or even just a music signal from another radio or tuner and using an oscilliscope or another amplifier such as is found in a “Heath” visual and aural signal tracer, or even a set of high impedance headphones with test prods on the ends. Then you can follow the signal path through the unit until the sound becomes distorted or disappears. Then you search around that area where the signal disappeared to resolve that issue.

When using a pair of old high impedance headphones, one lead can be clipped to the chassis. This allows you to apply a signal to the device being repaired and while powered up- starting from the input side of the circuit working your way through the audio chain along “Base” terminals of transistors until the signal drops out, or to the input terminals of signal IC’s (this is where you want to find the “Datasheet” for the device via it’s part number, such as “LSC 4558” so you can identify lead functions.) and their output. Where the signal disappears, is where to look for the issue. Electrolytic capacitors can dry out, short out, or just fail “open”. Transistors, IC’s or diodes can also just fail, or can partially fail causing a great deal of noise.

If a solid state unit appears to be just “dead”, check fuses (I have had fuses that looked okay, but had corroded through under the metal contact sleeve.) with a continuity tester regardless of their appearance, the rectifiers and power switch and cord to make sure they are okay. Then check the continuity of the transformer windings with the unit unplugged, then plug it in and see if you are getting the primary voltage (120 VAC nominally). If yes, then check secondary voltages. If no voltage is present in one or more areas of the power supply.

One of the often overlooked issues are the solder connections. In the late 50s into the 1960’s some antimony got into some solders. Antimony is not entirely stable and will break down leaving the remaining materials it was alloyed with porous (and sometimes deformed when too much of it is used in diecast parts.). When it fails in solders, the surface may appear okay, but underneath, the connection is weak and resistive. So if you have a device you are working on and nothing is apparent after everything has been checked over and nothing was out of sorts, reflow solder connections. If you are looking at some of the radiation detectors from that era made for the Civil Defense Department, many of those had components that had their leads were nickel plated, which in itself is a problem as it does not always alloy on the surface with the solder used.

Starting with units made about 1994, silver based solders were adopted as the solder of choice due to some innitiatives like RoHS (Reduction of Hazardous Substances) which phased out lead based solders among other things. The solders were also adopted readily because they were a little more durable for the Surface Mounte Devices (SMD’s) being introduced. The problem is the higher melting temperature solders also had a shorter period of transition from solid to liquid, so “cold solder joints” (weak and poor conductivity) were a more common problem than they had been previously. If nothing is apparent, and if you research to find if the company had poor quality controls in place, suspect bad solder joints. Polaroid TV’s had this affliction with sets made prior to their bankruptcy and reorganization.

Another thing to watch for is the older fiberglass PC boards- these are usually not heat tollerent, and you will have traces that lift easily no matter how good you are with sldering iron and sometimes the conductive rivits (eyelets) will also lift. Most PC/component boards were not meant to be serviced on the component level. But ChipQuik has a product intended for SMD device removal that aids in working with these fiberglass boards too. It is low melting point “desoldering alloy”.

Isolating what may be functional from what is not is largely a matter of logic- “does it work” or “does it not work”, and many service manuals have that type of breakdown for troubleshooting. However, there are times when some other factors may come into play that can derail that type of “decision tree”, but it is a starting point. Sometimes you can find a service manual or schematic online, sometimes not. A big part of troubleshooting is looking at the circuit to see what it does and evaluate why it may not be doing what it needs to do. Many times there are part number references inked onto the circuit board that have their location indicated in the schematic and are easy to locate in that manner. Again, if a schematic is not available, you can usually make some headway with an Application Note or Data Sheet from the maker of the IC. This is especially true with the newer digital TV’s and monitors.

With a simple amplifier, it is going to be basically a power supply, a preamp/driver stage, a power output stage and audio switching system to switch between inputs. If you are looking at a “Reciever” instead of a simple integrated amplifier, the only real difference is the tuning sections are part of the circuitry of the amplifier instead of being a separate component, and is switched essentially the same as it would be with the exception the power is also part of the input switching schema. With Things like modern TV sets, block diagrams can get complicated, but the issues usually settle in around the power supply, the inverter board for the backlight, the backlights themselves, and the display. Sometimes the board that controls the inputs develops an issue, and this is usually why people just swap boards rather than repair them at the component level- because sometimes additional failures developed as a result of capacitors failing.

##As complicated and involved as all of this sounds so far, as this is a broad subject. Once you have an idea of what each area of the amp, reciever, tape deck, etc is supposed to do, Power supply, Preamp, Voltage amp (Driver stage), Phase inverter, Power Amplifier, RF stage of recievers and tuners, etc- then it is a matter of determining what stages are working or what stages are not working. Typically in an amp, if the power supply is the fault, both channels are affected and in some cases the unit will just not turn on. In a Flat screen TV, the power supply is often the issue- usually capacitors, but sometimes another fault caused the problem and capacitors were just marginally functional.

In an amplifier that is stuck in “Protect” mode, it is usually an issue with the power amplifier stage, which can be failed transistors or failing capacitors and resistors that have failed as a result of the other component failures. Some use rectifiers as snubbers to protect the transistors, and these can fail. If Zener diodes were used and they are not marked, that can be a problem, but sometimes their voltage can be determined by test voltages when they are included in the service manual or schematic in locations close to the Zener diode. Sometimes if the problem develops after the repair, polarities of transistors, rectifiers and electrolytic capacitors and even tantalum capacitors should be checked. When working with power transistors, hybrid IC’s and some othe components that have special mounting hardware, that hardware has to go back into the original position. Some examples are mica insulators under power transitors, plastic screws and nuts or plastic washers to isolate the conductive parts of the device from the chassis or heatsink they were attached to.

This sums up the very basics of troubleshooting, and for some this may be enough to give a strong idea of what they need to do with other pieces of equipment. In the cases of power inverters, it is the same approach- find what is working and where it is not working and focus in that area in between. Some specifics on testing devices and components will be in one of the next posts.


The associated blog for above youtube channel

The main blog.
the begining point place to start

The tangential blog.

The passive solar blog- outgrowth from some projects of mine.

Posted in Advanced, Audio Amplifier, Back to Basics, Basics, Troubleshooting, Uncategorized | Tagged , , , , ,

Back to Basics: Soldering

Back to Basics: Soldering.

This is one of the most fundamental skills that one can develop because once you understand what you are doing, you can easily expand your horizons to soldering copper pipe (also known as “Sweating), to detail soldering either as a kit construction or as a repair some of the sophisticated brass models that are out there.

Technically soldering applies to lower melting temperatures solder alloys typically alloys of Lead, Tin, Antimony, Bismuth and these are sometimes components of bearing materials as well when the alloy contains Zinc or Aluminum: essentially those you can achieve a liquified state with a handheld soldering tool. When you get into the harder solders with higher melting points, that is technically called “Brazing” Which is a useful skill to have because some items are best repaired with brazing, and if working with high pressure copper tubing/piping, sometimes the requirement is for nothing less than a 90 percent silver filler material which requires over 700 degrees F to melt depending on what the other alloy material is.

What the soldering process is actually doing is it alloys the surface of one material to melt and bond with the filler material, which in turn alloys with the surface of the other material to alloy and bond to that other material. On the surface it seems simple enough, and it really is not that difficult to master.

What you need is a device for heating the connection, flux (to clean the material to be soldered), solder, and the pieces you are going to solder. For some this may seem overly simplistic, it is intended to cover the basics in a way that someone who has never done this type of work can develop that skill.
soldering tools
First, a word about solders. They are alloys of various metals, and they do have a lower melting point as an alloy than they do individually. Pure Tin and Pure Lead have a higher melting point than the various ratios of their alloys have. “Eutectic Solder” is one of 37% Lead and 63% Tin. It is the alloy that gives best results to those just learning, but if that is not available, work with you have. I have in a pinch made a soldered connection with just Lead, so it is possible to solder with the pure metals too. This happens to be how many terminated cables for automotive use were made. However with the push to RoHs compliance, lead is not being used any more. This causes some problems with some of the new electrical solders because they do not “wet” the surface of what is being soldered as well as the Tin/Lead solders did. Lead was banned from use in Copper plumbing for potable water in the US by 1985, which brought in Silver/Tin alloys which required a higher melting point than Tin/Lead, and “Silver/ Antimony/Tin alloys which melted at about the same point as Tin/Lead.

Some solders are “solid core” which just means it is wire of that alloy and needs some flux for use. “Flux Core” solders are common, and they work very well, and most use Rosin for electrical work and some use an acid core solder flux often Ammonium Chloride or “Sal Ammoniac”, which is intended for plumbing and architectrual uses and should never be used for electrical work. There are also other fluxes used for higher temperatures, such as Borax for the lower temperature brazing to some flouride compounds for higher temps. If you are wanting to know what the contents of your solder(s) are, the manufacturer should have Material Data Safety Sheets available with that information. Some of the newer RoHS compliant solders use alloys of Silver, Tin, Indium, Bismuth, Antimony, Copper, and some other metals.

The purpose of the flux is to react with the oxides and contaminants on the surfaces of the items being soldered. Rosin being a less active or less agressive flux, is not suitable for plumbing, but “can” be used if done so carefully, and items soldered with that as the flux should be rather bright to begin with. More agressive fluxes like Ammonium Chloride (Sal Ammoniac) are used in plumbing and structural uses (like rain gutters and architectural details, or with tinplate or zinc plated iron or steel.) due to it’s ability to react with oxides that might not have been able to be fully removed mechanically.

And the heat source. With architectural copper, brass, and other metals- torches burning propane, butane, methane, acetylene, etc are often used. Large soldering coppers are also heated by flame and are often used for copper and tin work along with large sodlering guns 300 to 500 Watt sizes. Because flame heated coppers are not entirely useful here, they just get a passing mention: but I have used smaller coppers that were made for electrical work in areas where either the conditions were not safe to use electrical devices or just not practical. I do also have an early post where I discuss how to fabricate some simple externally heated soldering implements, and in the image of the soldering implements I do have large copper (for electrical standards), but it is actually too small to do much work with it in architectural metalwork level.

For most electrical work/electronics work, soldering guns, such as those by Wen, Weller and others (which are little more than a transformer primary winding wrapped about a secondary that uses the tip to complete the circuit of the secondary and thus heat up directly) are used because they are quick to heat and are portable. There are some resistance soldering systems that work in a similar method but their tips are not completing the circuit until they are both in contact with the same conductive piece (resistance welding is a similar process that uses enough current to heat the wire (or sheet material) to melting/fusing temperature without solder. Commonly used to connect thermal fuses and multi-cell rechargable batteries.). Resistance soldering is more common in the construction of Brass models, though it sometimes is carefully used with Surface Mount Devices. And then there are soldering “irons”, which is just a heated element near the tip of the tool that indirectly heats the tip itself. There are sophisticated soldering irons that allow for precise temperature control, and these are useful in some applications, but there is a bit of a learning curve to get it set right for soldering or de-soldering with the different alloys that are out there.

soldering tools

With soldering guns, there are different wattages, which produce different heat levels, which can be a rough guide for selecting one. For many point to point construction projects a gun sized between 60Watts and 150 watts will usually suffice. If you a lot of deconstructing, a 300 Watt soldering gun may on the surface look absurdly large, the reality though is it generates a lot of heat quickly so the heat being drawn away from the fusion zone or into a device to salvaged is not significant enough to cause problems of melting the solders elsewhere or damaging the board. Now for fine work on small boards, the physical size makes them clumsy at times, and the tips can be rather large and therefore innaccurate for precise soldering. You do need to have some situational awareness about you when using anything as hot as a soldering tool, but you especially need to be cognizant of what is around the tool because a momentary lapse is enough to melt things like wire insulation that you really do not want to be melting, or melting plastic cosmetic/face plate items, or worse- causing yourself or others burns. Soldering guns occupy much more physical space than the soldering irons, so close work should be approached with the smaller soldering irons.

If you are on a budget and cannot afford a sophisticated soldering station (which have come down in price considerably from where they were 20 years ago), smaller soldering irons can work, and are preferred for working on printed circuit boards. The problem with smallest ones is they do not get hot enough to melt some of the RoHS compliant solders used in manufacturing. In other words, a 20 watt iron is borderline for Tin/Lead solders, but not usually adequate for higher temp silver alloy solders that are RoHS compliant. 25 Watt is a more practical size for most things, but it will get hot enough if used long enough to lift solder tracks from printed circuit boards, but depending on tip, may or may not be hot enough to melt RoHS solders quickly, which is an issue for rework or salvage. Plus some substrates are not heat tollerant. Those boards that you see with a “94” in the conductive foil- those are flame resistant, and tend to be much more stable and thus easier to work with when doing repair work, but are not indestructible. Those that do not have that marking and resemble fiberglass in resin- those are dificult boards typically and not fire resistant, plus the board itself will melt easily. Phenolic boards are consistently the best to work with.

Now the basic techniques;
*First is to make sure the conductors to be soldered are as clean as they can be- if not, they will require extra heat and time, which may lead to melted insulation. Sometimes that oxide layer cannot be avoided, or the wire is too weak to attempt removal of the varnish- these are situations where you just apply heat and solder until the wire gets wetted with solder.
*Second, make the connection as mechanically sound as possible. If splicing wires and using heat shrink tubing to cover the repair, you need to move the tubing far enough away from the joint that it does not begin to shrink too early, and you need to make sure the ends of the wires are flat enough to allow easy passage of the tubing over the splice. If the connection is to be exposed to weather, heat shrink by itself is not enough, and sometimes if multiple wires are to be soldered together, there is not an easy way to apply heat shrink. In that event, apply some RTV to the joint after it has been soldered, and over the ends of the heat shrink tubing if it was used, then before the silicone has a chance to set up (cure) apply some “Self Vulcanizing” tape (such as 3M’s “Oakanite” tape) over the spliced area. Between the two, the wires should be weatherized well enough to last many years. If this is not done, the splice can be a point of failure in a short period of time as water will be drawn under the insulation by capillary action and cause corrosion. If the connection is underneath a vehicle, and therefore exposed to salts or other de-icing materials, the wire will corrode through sooner.
*Third, apply heat to the connection to be soldered with your soldering tool of choice. Make sure the tip of the soldering tool is clean and tinned, and apply heat to both surfaces to be fused with solder. Once the surfaces are hot enough to melt solder dabbed at the joint, pay attention to where and how it is flowing. If it coats both surfaces easily, apply enough solder to coat the wires (of a splice) or leave a small “cone” of solder when soldering to a printed circuit board. Once that has been achieved, then you can remove heat with a wiping motion along the wire or component lead and allow the joint to cool- but do not disturb the joint until after the solder has solidified.

*If attempting to solder a wire to a metal chassis in a radio, amp or other audio equipment, first heat just that chassis and apply solder. It may require the tip to be in motion scraping the surface slightly to get some solder to fuse, but once a puddle of solder is created, while continuing to heat the pool, place the wire being soldered into place into the pool and then remove heat. Hold things steady and do not move the wire until the solder has solidified.

Aluminum will not accept electrical solder, nor will zinc castings- however zinc plated iron will accept solder fairly readily. Brass is not normally considered to be very easily soldered, but if it is clean, and fluxing is adequate, it will solder quite well. (this does not count the specialty solders/brazing materials that will alloy with the zinc or diecast alloy)

*Always keep flamables away from soldering equipment and unplug them after use. The use of a holder that can disipate heat if the iron is forgotten is a really good idea. Good ventilation no matter what solders are used is a good idea. Correct clothing- flux can spatter when heated, and acid core solders can cause chemical burns as well as thermal burns. So if you do not wear glasses, it would be prudent to get some safety goggles. And always pay attention to where the tip of the soldering tool is at all times. Don’t wear short pants, or you will get some burns.

The bottom line is the basic techniques are described above. The location of the soldering implement in relation tot he environment or the pieces being soldered will vary- however the more comfortable you are, the more reliable the soldered connections will be. Environmental factors just depend on where and which direction the heat can be applied to the joint to be soldered most comfortably. Use an implement of adequate heat for the job. And pay attention to where the tip is at all times. It takes a little getting used to, but like welding, it is something you have to develop your own “feel” for it. You will see when things are accepting a “tinning coat”, then it is merely a matter of developing a feel for when you have applied the right amount of solder as opposed to too much solder as opposed to too litlle solder. If you are soldering to a printed circuit board, the solder pad should be covered, the wire lead should be fully surrounded with solder, but only enough to form a little cone of solder where the cone edges are slightly concave, and not convex (too much solder). Wire wrapped in terminal strip loop is adequately soldered if it cannot move, and the wire is evenly coated with solder yet thin enough to reveal detail of individual strands. It is not a requirement that the terminal loop be filled with solder, but the loop should be wetted with solder in the vicinity of the fusion zone.

This post may get a video posted later, but should be detailed enough to get those new to the concept of soldering with a soldering implement up to speed and soldering reliably.


an old house renovation blog

The main blog.
the begining point place to start

The tangential blog.

The passive solar blog- outgrowth from some projects of mine.

Posted in Alternative Energy, Alternative Energy Circuits, Alternative Energy Circuits for "Homebrew", Back to Basics, Basics, Solder, soldering, Uncategorized | Tagged , , , , , , , , , , , , , ,

Taming an LM386

Sometimes doing some sound reinforcement work, I have found a need for a small preamp with some gain, but not a lot. One IC that works very well in this service is the venerable LM386. The LM386 chip has evolved from what it once was and is currently available in 3 “flavors”. The LM386-1 and LM386-4 are respectively 3/8 Watt and 3/4 Watt output- However that rating is into 8 ohms. So if you are looking for modest gain into a 10,000 ohm load, that wattage rating is not important as you will not be driving the the input of the next stage to the point of failure, but you can drive that input stage into “overdrive” for guitar effects.

The LM386-7 is the one watt rated output, which will still work as a low gain voltage amplifier into an amplifier input. I built a pair of them back in the 1970’s to drive a low impedance headset microphone into a high impedance intercom system and they worked quite well.

One thing that is not discussed in the datasheet or application notes is “quieting” the LM386. If they are put “back to back” on the same circuit board they can get noisy, plus some are just inherently noisy by themself in spite of reasonable noise specs. The noise I refer to with these is in the form of “noise floor” (the sound of the amp and or preamp with zero input signal.). To deal with this is rather simple- just a 0.1 microfarad disk capacitor will do it, and is best located below the IC or IC socket between pin4 and pin 6,. That is all it takes to make the amps behave. This is especially true on battery supplies.

The other factor is gain. It is “adjustable” by the choice of components, or lack thereof, between pins 1 and 8. The way to make that gain adjustable via control knob is to simply add a potentiometer between pin 1 and the 10 microfarad capacitor connected to pin 8. The maximum gain is about 200, if that resistor is about 1.8K, the gain is 50. So depending what gain you are seeking for low end, you want a potentiometer of at least 10K, but 100k and 1 meg choices may give better low gain results, but you do risk introducing some noise.

LM386 schematic

An LM386 with adjustable gain

It is best to not use a higher resistance pot than 10K on the input. If you do, you introduce noise into the circuit, plus you can begin to have issues with input voltage offset. Additionally, that input pot can be omitted, but a 10K resistor between the input and ground should be installed to maintain the input at the design potential. A lower value could be used experimentally to find the correct value if input offset voltages become an issue.

From the data sheets, the above circuit with just a 10 microfarad capacitor across pin 1 and 8 yields the maximum gain this chip has to offer, which is a gain factor of 200. Leaving pins 1 and 8 open leaves the chip at it’s lowest gain of 20. If driving a power amp from an MP3 player with the LM386 as the voltage amplifier, all you need is a gain factor of 20 to drive the amp (more than) adequately.


an old house renovation blog

The main blog.
the begining point place to start

The tangential blog.

The passive solar blog- outgrowth from some projects of mine.

Posted in Audio Amplifier, Audio circuit, Project, Uncategorized, voltage amplifier | Tagged , , , , ,

Uncommon sense?

This post is interuppting the back to basics informaiton here just to touch on some simple matters to keep in mind when you build a system. Also keep in mind that most electricians who have done any amount of work give the most respect to DC circuits because if your body completes a circuit, your muscles clamp down; the chances of breaking loose from that are not very high. AC power in single phase at least crosses the zero point reference 60 times per second (In North America), so you have some chance to pull free if you are able to mantain focus. Three phase power is very similar to DC concerns, but chaces are more likely that if you get careless that you tie into one leg of the 3 phases and you get thrown across the room if you are lucky. But if you should be unlucky and tie into 2 or 3 of the phases, you get burned pretty bad and it becomes difficult for you to try to break free. This is not idle musing, I have worked with and talked to a number of electricians, all of whom can tell you stories of first hand and eyewitness accounts. I have mentioned previously as well that musicians have been killed by wiring faults when they have grabbed a microphone stand- which is why many of them hit the stand with the back of their hand to see if it is safe, because you will still feel it if it is not safe.

Battery location is important because you do not want them getting wet, but sometimes they need placement outdoors. No matter where you put them, when the space becomes enclosed, there is a chance for a hydrogen explosion. Even in well vented areas there is a chance a battery itself will explode if there is a loose plate connection internally or even externally. So no matter where you put them, 1), you want to make sure if one explodes, that it is contained within the cabinet. 2), You want to make sure ventillation is better than simply adequate. 3), There are no ignition sources (switches, relays) that could trigger an explosion within the cabinet or space.

Hydrogen is lighter than air, so holes at the bottom of the containing cabinet are not adequate by themselves because of the lighter than air nature of hydrogen- however if you add vents at the highest point(s) and in high pockets where hydrogen may accumulate, those bottom vents are helpful.

There are some methods of venting for tightly enclosed spaces such as a sealed rack cabinet, or suppose you are using an old freezer cabinet. At some point in the near future I will actually show images of such a conversion, but for now I will just mention that you cannot rely on just some simple vent holes at the top, and in applications where the access to the lower portions of a cabinet are not feasible, such as on a boat, you have to approach things a little differently as you also need to factor in the potential for water to splash into a vent.

You can find some different schemes online, but the simplest one I have found is simply a hole simply large enough to accept 2 inch PVC pushed through the side of the storage compartment, but it can be through the top as long as the PVC is then flush with the top inside of the cabinet to prevent Hydrogen accumulation. The 2 inch PVC through the side only needs to go in a few inches- and it must be at the highest point practical. Inside of that 2 inch section, you slip a 1 inch PVC pipe and you want it to clear the length of the 2 inch portion, but to the horizontal 1 inch piece, you will add a 90 degree elbow, with a length of 1 inch PVC that extends down to the bottom of the cabinet, about 1 inch above the bottom deck of the container, so the 1 inch pipe only needs to extend beyond the 2 inch PVC by just enough for the fitting to clear. (You can get sophisticated and drill a hole through the 2 inch PVC sidewall to allow a 1 inch fitting to poke through, and then glue the pipe to go downward intot he fitting, thus making the 1 inch assembly “captive” to the 2 inch piece.) This assembly you will want to have extend out from the container, primarily the 1 inch pipe, even up to actually drawing in vent air from outside of the structure. This assumes the main space of the area surrounding the batteries and container is well enough vented (or drafty) to allow the hydrogen to disipate rather than collect. If it is weather tite space as well, then you definitely want the 2 inch piece to go outdoors as well. Running both intake and hydrogen exhaust outdoors is the best setup, and the only real consideration is the 1 inch PVC must be extended beyond the 2 inch PVC section. If there is a slight upward angling of the assembly to outdoors, that is the best- perhaps 1/4 inch per foot of run, which is the rule of thumb for plumbing in general. The assembly should never point downward out of the container/containment as that will allow for hydrogen to accumulate.


A rudimentary drawing of a cbinet with a side vent and top vent.

The assembly works because the hydrogen is able to move out of the cabinet, which creates a slight draw for air to come in, but you want the incoming air to come in at the bottom of the cabinet to reliably displace or make up what hydrogen flows out- this method is reliable and simple.

Make sure your wiring is sized adequately- it is okay for it to be a larger diameter cable or wiring than electrical code tables suggest. Keep your lower voltage runs as short as practically can be achieved. For a specific example: a 2 volt drop is to be expected with 16 gauge wire in a 25 foot run operating at 12 volts. This can be a huge impact on certain lighting schemes. Strongly consider adding a main switch to lock out the input to the battery array, and to lock out the battery power to the system buss. Make sure that the switch can be physically locked to prevent someone from accidently applying power- which is a standard practice with industrial equipment maintanance.

Be consistent with your wiring colors. Because black in low voltage often has a diffent meaning than black in a 120/240 wiring scheme (industrial or residential). It is an absolute MUST to be consistent and make notes to that affect for whomever may service the system in the future. For example, with some import vehicles, the black wire has the same basic wiring reference as house wiring. So be consistent. If white is you low votage “return”, as it is with your house wiring, keep it that way. That makes your Black wire your “hot”- to be consistent with house wiring practices. Most of your panels are going to be wired from the factory for black for negative and red for hot or “+”, so be consistent up to the battery bank- and make your notes visible at the battery bank as to what your wiring past the battery bank is or is to be.

Keep your wiring tidy and organized. If you are looking to keep your homeowners insurance, get the wiring inspected when it is in your home or office space. When this wiring is installed in a summer cottage, backwoods cabin, RV, etc- even though it may not be inspected: do the work to a quality level where if it were to be inspected- that it would pass. This is mainly a safety issue. Which means you should also be sure to use fuses or manually resettable circuit breakers in the voltage range of your power buss. This also means a fuse or breaker between panels and batteries and batteries and power buss.

These guidelines apply to any alternative power system.

Some cautions with Solar panels are do not flex them, they will break unless they are made on a flexible substrate. Keep wire and cable ends insulated and taped when working on them during the day, Many AC arc welders operate at 12 to 30 volts, which means a 75 Watt Panel, can weld 1/4 inch steel int he right circumstances- so handle the cables with care. If you are lucky in mishandling one, you just get some burns, however if circumstances are correct you can die.

The same is true with wind systems, if the hub cannot be locked down, or the mill furled, you face a very real situation of electric shock, burns, or death. This is no joke.

You also need to make some “Earth ground” connections with ground rods driven into the soil to disipate static electricty buildup, lightning strikes, etc, whether wind, solar, steam or hydro.

As mentioned in a previous post, do not just assume your roof can handle solar panel arrays, wind will add a lifting force to the roof structure, and the panel array will have weight. The roof needs to be adequate to handle both, and ideally the walls of the structure are also “wind tied” to prevent roof failure in high winds.

Something to be aware of with wind systems- conventional horizontal axis mills, there will be some “strobing” from the propeller, with some VAWT systems this can be an issue too and where shadows fall can impact property value, or neighbor’s attitudes. Some people get headaches from the strobing effect, and some people can actually develop epileptic seizures triggered by the strobing. While strobing shadows are a bit less of an issue with small wind systems, they are still some concern. Strobing can be an issue of significance with larger wind systems, especially the big wind systems where those shadows may fall outside of the property lines. This may seem insignificant and a trivial concern until you have seen some of the impacts big wind systems have had on residents close to the wind systems visually. Normally such issues develop after the installation because no one considered those effects ahead of time.

Wind systems may also generate some degree of noise. Some don’t mind some of the noises when they are low level with small systems, but big wind systems have been known to generate significant noise. So placement and screening vegetation is also a consideration.

Also mentioned previously are the health issues with PVC blades- they will fatigue, and break or bend and hit the tower and break. Where those pieces go is always a concern because they have enough mass to them when in flight to actually kill a person. It is for that reason I am dismissive of any such plastic “home made” blades- even those that may be deemed “commercial- if made of PVC- they are a major health hazard within 1000 feet of the mill. Metal blades and wooden blades are not perfect either, and can injure or kill as well, but they will usually give visual indications of a pending failure before an actual failure occurs if you take the time to inspect them on a regular basis. Even the well made commercialy manufactured composite blades pose some risks when they fail, but their reliability is so far above that of PVC, that they can be considered to be much safer overall.

This is just uncommon sense- since people will argue over what IS common sense. When factor in the fact there are plenty of people supportive of PVC as a blade material who should know better, that I have to call this “uncommon sense” because PVC is never safe so should never even be considered for blade material. ABS pipe is even worse.

Always keep your wits about you and also be situationally aware when handling the parts and all times during the installations or repairs so you do not injure someone. This is especially true when working on roofs or on a tower, they have their own safety considerations.

Also with wind- pick your tower location with regards to where it may collapse- pick a location that is least risk to people in the event of a tower failure.

I also advise against trying to “run your power meter backwards” because it is not safe for anyone working on the power lines unless you install a remote “cutout” where the power company can remotely shut off your system, usually installed by a contractor the power company hires to do the work. In many areas the meters are being changed over to “smart meters”, and one facet of their operation is to detect any attempt at applying power to the grid from a home power system. While “Home Power” magazine praises these people and gives them space, it is going to be costly for those people in the future as the new meters have a unique identifier number so the power company will know the instant someone tries to plug their inverter into the wall outlet to attempt to run a meter backwards, not to mention that “Home Power” magazine is irresponsible for what it has promoted, and when the magazine just looks like a sales brochure in it’s content- it is not worth the purchase price at any price and just not worth bothering with it. My position has been consistent and clear- If you are going to make a large or small investment in equipment for home use- just keep it home because you can find plenty of things to put that power to in order to reduce overall energy usage in the home.


an old house renovation blog

The main blog.
the begining point place to start

The tangential blog.

The passive solar blog- outgrowth from some projects of mine.

Posted in altencircuits, Alternative Energy, Alternative Energy Circuits, Alternative Energy Circuits for "Homebrew", alternators, Batteries, Battery care, Charge Controllers, Charging Circuit, DC to AC Inverters, Dynamo, Emergency power option, Generators, Health, Low Voltage Lighting, Power Inverters, Solar Power, Uncategorized, VAWT, Wind Turbines | Tagged , , , , , , , , , , , , , , , , , ,