admin Comment(0)

ELECTRONICS REPAIRING AND LEARNING CIRCUITS FOR FREE This eBook shows you how to TEST COMPONENTS. To do this you need "TEST .. code chart: Download the program and save it on your desk-top for future reference. A great electronic repair troubleshooting tips and secrets for the technicians and engineers. Want To Learn Electronic Repair The Easy Way? Its free so download now. New LCD TV SMPS Repair Ebook By Damon Morrow. Please click. Download The Laptop Repair Workbook An Introduction to Troubleshooting and Electronics Repair Manual By Gene B. Williams, Joseph

Language: English, Spanish, Japanese
Country: Cyprus
Genre: Environment
Pages: 380
Published (Last): 19.01.2016
ISBN: 813-4-50141-299-1
ePub File Size: 15.73 MB
PDF File Size: 17.31 MB
Distribution: Free* [*Free Regsitration Required]
Downloads: 21604
Uploaded by: MACKENZIE

pop pianist, and a published songwriter. Along with building and repairing electronic circuitry, he enjoys table tennis, restoring old mopeds, ice skating, bicycling. Editorial Reviews. About the Author. Michael Jay Geier has been an electronics technician, eBook features: Due to its large file size, this book may take longer to download Read with the free Kindle apps (available on iOS, Android, PC & Mac), Kindle A Fully Revised Guide to Electronics Troubleshooting and Repair. Looking for books on Electronic Circuits? Check our section of free e-books and guides on Electronic Circuits now! This page contains list of freely available.

Its free so download now. Bench Power Supply Repaired. Click here to sign up free to become a member. Click HERE to read the rest of the article. Sony Alarm Clock Repaired.

We will begin to search for the answer in the internet, books and electronic repair magazine, forums and from our fellow repair friends. Though sometimes it was quite time consuming , we still enjoy it. Electronic repair is a skill and once you had mastered it, no one can snatch your knowledge away. Many electronic enthusiast treat this as a hobby but it also could help them in generating incomes by repairing electronic equipments.

My sincere hope, is that this resource will help you to be able to tackle electronic problems as quickly and painlessly as possible.

All the best! Jestine Yong. Subscribe To My Free Newsletter. Stay up to date with all the latest Electronic. Techniques and much, Much more. Click here for details. These pages are intended to assist in the repair of electronic equipment and we have attempted to ensure this website is as accurate as possible. However, ElectronicRepairGuide accepts no responsibility for any loss, injury or inconvenience sustained by anyone resulting from this information.

Please be careful as all electrical equipment is potentially dangerous when dismantled. Copyright www. Free Newsletter. If the bar is longer, the resistance is higher. If the material of the bar is changed, the resistance is higher. It's a bit like standing on a hose. The flow reduces. When current flow is reduced, the output voltage is also reduced and that why the water does not spray up so high.

Resistors are simple devices but they produce many different effects in a circuit. A resistor of nearly pure carbon may be 1 ohm, but when non-conducting "impurities" are added, the same-size resistor may be ohms, 1, ohms or 1 million ohms. Circuits use values of less than 1 ohm to more than 22 million ohms. The letter "E" is also sometimes used and both mean "Ohms. The size determines the wattage of the resistor - how much heat it can dissipate without getting too hot. Every resistor is identified by colour bands on the body, but when the resistor is a surface-mount device, numbers are used and sometimes letters.

If 3rd band is gold, Divide by 10 If 3rd band is silver, Divide by to get 0. The first 3 bands produce the resistance and the fourth band is the "tolerance" band.

These two bands provide the digits in the answer. But it's easy to follow. This represents a ZERO in the answer. This is different to 4-band resistors where black represents the word OHMS!

The following list covers 10 ohms 10R to 1M. Surface Mount Resistors. All the SM resistors in the above photos conform to a 3-digit or 4-digit code.

But there are a number of codes, and the 4-digit code caters for high tolerance resistors, so it's getting very complicated. Here is a basic 3-digit SM resistor:. A k SM resistor. Three Digit Examples. Four Digit Examples. If you want to create a "Special Value," simply connect two resistors and read the value with a Digital Meter.

Keep changing the values until you get the required value. We are not going into series or Parallel formulae. You can easily find a value with a multimeter. You simply ADD the values. This can be done with any to two values as shown. Three equal-value resistors in series is three times the value.

Three equal-value resistors in parallel is equal to one-third the value. If you want a particular value and it is not available, here is a chart. Use 2 resistors in series or parallel as shown: There are other ways to combine 2 resistors in parallel or series to get a particular value. The examples above are just one way. The surrounding components can affect the reading and make it lower. You can take the reading of a resistor "in-circuit" in one direction then the other, as the surrounding components may have diodes and this will alter the reading.

You can also test a resistor by feeling its temperature-rise. Resistors are just "resistors" and they can be in AC circuits or DC circuits. It is a low-value resistor and has a voltage-drop across it but this is not intentional. The voltage-drop is to create a "heating-effect" to burn out the resistor. In all the other types of resistor, the voltage-drop is intentional. A Ballast resistor is a normal resistor and can be called a Power resistor, Dropper resistor, Supply resistor or Feed resistor.

It is designed to reduce the voltage from one source and deliver a lower voltage. It is a form of: A Load Resistor is generally connected across the output of a circuit and turns the energy it receives, into heat. It is made with many resistors of the same value, all in one package.

One end of each resistor is connected all the other resistors and this is the common pin, identified as pin 1 and has a dot on the package. These packages are very reliable but to make sure all the resistors are as stated, you need to locate pin 1.

All values will be identical when referenced to this pin. Some resistor networks have a "4S" printed on the component. The 4S indicates the package contains 4 independent resistors that are not wired together inside. The housing has eight leads as shown in the second image. Independent resistors have an even number of pins and measuring between each pair will produce identical values.

R esistance between any pair will indicate leakage and may be a fault.

Electronics Repair

When cold, it has a very low resistance and a large current flows when the monitor or TV is switched on. This current heats up the Posistor and the resistance increases. This causes the current to decrease and any magnetism in the shadow mask is removed. The posistor can one or two elements and it is kept warm so the resistance remains high. Many Posistors have a second element inside the case that connects directly to the supply to keep the Positive Temperature Coefficient resistor high so that the current through the degaussing coil falls to almost zero.

This constant heat eventually destroys the package. The heavy current that flows when a set is turned ON also causes the posistor to crack and break and this results in poor purity on the screen - as the shadow mask gradually becomes magnetic..

Posistors have different resistance values from different manufacturers and must be replaced with an identical type. They can be checked for very low resistance when cold but any loose pieces inside the case will indicate a damaged component. The resistance of a "burnt" resistor can sometimes be determined by scraping away the outer coating - if the resistor has a spiral of resistance-material.

You may be able to find a spot where the spiral has been damaged. Clean the "spot" burnt section of the spiral very carefully and make sure you can get a good contact with the spiral and the tip of your probe. Measure from one lead of the resistor to the end of the damaged spiral. Then measure from the other lead to the other end of the spiral. Add the two values and you have an approximate value for the resistor. You can add a small amount for the damaged section. This process works very well for damaged wire-wound resistors.

They can be pulled apart and each section of the resistance-wire nichrome wire measured and added to get the full resistance. There is another way to determine the value of a damaged resistor. Get a set of resistors of the same wattage as the damaged component and start with a high value. It's handy to know if the resistor is in the range: Start with a very high value and turn the circuit ON. You can perform voltage tests and if you know the expected output voltage, decrease the resistance until this voltage is obtained.

If you do not know the expected voltage, keep reducing the value of resistance until the circuit works as designed.

This is the best advice in a situation where you do not know the value of a resistor. There is a third way to determine the value and this requires measuring the voltage drop across the resistor and the current-flow. By multiplying the two you will get a wattage and this must be less than the wattage of the resistor being replaced.

A Rheostat is a variable resistor using only one end and the middle connected to a circuit. The resistance between the two outside pins is the value marked on the component and the centre leg will change from nearly zero to the full resistance as the shaft is rotated. Cleaning with spray fixes the bad focus but if the pot is leaking to chassis from inside the pot due to the high voltage on the terminals simply remove it from the chassis and leave it floating this will restore the high voltage to the picture tube or you can use one from an old chassis.

We have already covered placing resistors and capacitors in parallel and series: Two 1k 0. Zener diodes can be connected in series to get a higher voltage. Two 12v zener diodes in series produces a 24v zener. You can use the resistance scale "x1" or "x10" to detect low values of resistance. Set the pointer to "0" right end of the scale by touching the probes together and adjusting the "zero ohms" control.

When taking a reading, you will have to decide if a low value of resistance is a short-circuit or an "operating value. The "resistance of a circuit" may be very low as the electrolytics in the circuit are uncharged. This may not indicate a true "short-circuit. Leads and wires and cords have a small resistance and depending on the length of the lead, this small resistance may be affecting a circuit. Remember this: When a circuit takes 1 amp, and the resistance of the leads is 1 ohm, the voltage drop across the leads will be 1v.

That's why a 12v battery supplying a circuit with these leads will have 11v at the circuit. Turn off the equipment before making any continuity tests.

The presence of even a small voltage from an electrolytic can give a false reading. You can determine the resistance of a lead very accurately by taking the example above and applying it to your circuit.


If the battery is By making the lead shorter or using thicker wire, the resistance will be less and the voltage on the project will increase. When taking readings in a circuit that has a number of diodes built-into IC's Integrated Circuits and transistors, some Continuity Testers will beep and give a false reading. The following circuit has the advantage of providing a beep when a short-circuit is detected but does not detect the small voltage drop across a diode.

This is ideal when testing logic circuits as it is quick and you can listen for the beep while concentrating on the probe. Using a multimeter is much slower. You can build the circuit on Matrix Board and add it to your Test Equipment.

You will need lots of "Test Equipment" and they can be built from circuits in this eBook. Turn off all power to the equipment before testing for shorts and continuity. All fuses, leads and wires should have a low, very low or zero resistance. This proves they are working. If the inside of the glass tube of the fuse is totally blackened, the fuse has been damaged very quickly.

This indicates a very high current has passed through the fuse. Depending on the rating of the fuse, current rating you will be able to look for components that can pass a high current when damaged - such as high power transistors, FETs, coils, electrolytics.

This is done by measuring them on a low OHMs range in one direction then reverse the leads to see if the resistance is low in the other direction.

A reading can be very low at the start because electrolytics need time to charge-up and if the reading gradually increases, the power rail does not have a short. An overload can occur when the supply voltage rises to nearly full voltage, so you sometimes have to fit a fuse and see how long it takes to "blow. They are all current ratings as a fuse does not have a voltage rating.

Some fuses are designed for cars as they fit into the special fuse holders. Some fuses are fast-blow and some are slow-blow. A "normal" fuse consists of a length of thin wire. Or it may be a loop of wire that is thin near the middle of the fuse.

This is the section that will "burn-out. For instance, a 1amp fuse will remain intact when up to 1. When a circuit is turned on, it may take amps for a very short period of time and a normal 1 amp fuse will get very hot and the wire will stretch but not "burn-out.

If the current increases to 2amps, the fuse will still remain intact. It needs about 3 amp to heat up the wire to red-hot and burn out. A slow-blow fuse uses a slightly thicker piece of wire and the fuse is made of two pieces of wire joined in the middle with a dob of low-temperature solder.

Sometimes one of the pieces of wire is a spring and when the current rises to 2. Thus the fuse is not gradually being damaged and it will remain in a perfect state for a long period of time. A fuse does not protect electronic equipment from failing. It will then protect a power supply from delivering a high current to a circuit that has failed.

If a slow-blow fuse has melted the solder, it could be due to a slight overload, slight weakening of the fuse over a period of time or the current-rating may be too low. You can try another fuse to see what happens. You can replace a fast-acting fuse normal fuse with a slow blow if the fast-acting fuse has been replaced a few times due to deterioration when the equipment is turned on.

But you cannot replace a slow-blow fuse with a fast acting fuse as it will be damaged slightly each time the equipment is turned on and eventually fail.

The wire may be wrapped around a core made of iron or ferrite. It is labeled "L" on a circuit board. You can test this component for continuity between the ends of the winding and also make sure there is no continuity between the winding and the core.

The winding can be less than one ohm, or greater than ohms, however a coil of wire is also called an INDUCTOR and it might look like a very simple component, but it can operate in a very complex way. The way it works is a discussion for another eBook. This causes the fuse to "blow. You can then compare the inductance with a known good component. An inductor with a shorted turn will have a very low or zero inductance, however you may not be able to detect the fault when it is not working in a circuit as the fault may be created by a high voltage generated between two of the turns.

A TV or monitor screen is the best piece of Test Equipment as it has identified the fault. It is pointless trying to test the windings further as you will not be able to test them under full operating conditions. The solution is to measure a larger inductor and note the reading. This way you can measure very small inductors.

However these components can become intermittent due to dirt or pitting of the surface of the contacts due to arcing as the switch is opened. It is best to test these items when the operating voltage and current is present as they quite often fail due to the arcing.

A switch can work 49 times then fail on each 50th operation. The same with a relay. If the contacts do not touch each other with a large amount of force and with a large amount of the metal touching, the current flowing through the contacts will create HEAT and this will damage the metal and sometimes reduce the pressure holding the contact together. This causes more arcing and eventually the switch heats up and starts to burn.

Switches are the biggest causes of fire in electrical equipment and households. A relay also has a set of contacts that can cause problems. There are many different types of relays and basically they can be put into two groups. The contacts allow a current to flow and this current can damage the contacts. Connect 5v or 12v to the coil or 24v and listen for the "click" of the points closing. Measure the resistance across the points to see if they are closing.

You really need to put a load on the points to see if they are clean and can carry a current. The coil will work in either direction. The two pins that energise the relay the two input pins must be connected to 5v or 12v around the correct way as the voltage is driving a LED with series resistor. The LED illuminates and activates a light-sensitive device. That's because they don't give a reading on a multimeter and their value can range from 1p to ,u. A faulty capacitor may be "open" when measured with a multimeter, and a good capacitor will also be "open.

Both are correct and you have to combine them to get a full picture. But it works in another way. Suppose you have a strong magnet on one side of a door and a piece of metal on the other. By sliding the magnet up and down the door, the metal rises and falls. The metal can be connected to a pump and you can pump water by sliding the magnet up and down. A capacitor works in exactly the same way. If you raise a voltage on one lead of a capacitor, the other lead will rise to the same voltage. This needs more explaining - we are keeping the discussion simple.

It works just like the magnetic field of the magnet through a door. The next concept is this: Capacitors are equivalent to a tiny rechargeable battery. They store energy when the supply-voltage is present and release it when the supply drops.

These two concepts can be used in many ways and that's why capacitors perform tasks such as filtering, time-delays, passing a signal from one stage to another and create many different effects in a circuit. The easiest way to understand capacitor values is to start with a value of 1u.

This is one microfarad and is one-millionth of a Farad. A 1 microfarad capacitor is about 1cm long and the diagram shows a 1u electrolytic. Smaller capacitors are ceramic and they look like the following. This is a n ceramic: To read the value on a capacitor you need to know a few facts. Capacitors from 1p to n are non-polar and can be inserted into a circuit around either way. They must be fitted so the positive lead goes to the supply voltage and the negative lead goes to ground or earth.

There are many different sizes, shapes and types of capacitor. They are all the same. They consist of two plates with an insulating material between. The two plates can be stacked in layers or rolled together.

The important factor is the insulating material. It must be very thin to keep things small. If a capacitor sees a voltage higher than its rating, the voltage will "jump through" the insulating material or around it. If this happens, a carbon deposit is left behind and the capacitor becomes "leaky" or very low resistance, as carbon is conductive. This is especially true for surface-mount capacitors. All capacitors are marked with a value and the basic unit is: For testing and repair work, they are all the same.

Simply replace with exactly the same type and value. A tantalum is smaller for the same rating as an electrolytic and has a better ability at delivering a current.

They are available up to about 1,u, at about 50v but their cost is much higher than an electrolytic. Electrolytics are available in 1u, 2u2 3u3 4u7 10u, 22u, 47u, u, u, u, u, 1,u, 2,u, 3,u, 4,u, 10,u and higher. The "voltage" or "working voltage" can be: There is also another important factor that is rarely covered in text books.

This is the amount of current that can enter and leave an electrolytic. This current heats up the electrolytic and that is why some electrolytics are much larger than others, even though the capacitance and voltage-ratings are the same. If you replace an electrolytic with a "miniature" version, it will heat up and have a very short life. This is especially important in power supplies where current energy is constantly entering and exiting the electrolytic as its main purpose is to provide a smooth output from a set of diodes that delivers "pulsing DC.

It sometimes has the letters "NP" on the component. Sometimes the leads are not identified. This is an electrolytic that does not have a positive and negative lead but two leads and either lead can be connected to the positive or negative of the circuit. A non-polar electrolytic can be created from two ordinary electrolytics by connecting the negative leads together and the two positive leads become the new leads.

For example: In the circuit below, the non-polar capacitor is replaced with two electrolytics. If you do not have the exact value, two or more connected in parallel or series can produce the value you need. Capacitors connected in series will produce one with a higher voltage rating. Capacitors connected in parallel will produce a larger-value capacitance. Here are examples of two equal capacitors connected in series or parallel and the results they produce: This specifies the maximum voltage that can be applied across the capacitor without puncturing the dielectric.

Voltage ratings for "poly," mica and ceramic capacitors are typically 50v to VDC. Ceramic capacitors with ratings of 1kv to 5kv are also available. Electrolytic capacitors are commonly available in 6v, 10v 16v, 25v, 50v, v, v, and v ratings. CAUTION If a capacitor has a voltage rating of 63v, do not put it in a v circuit as the insulation called the dielectric will be punctured and the capacitor will "short-circuit. High voltage electrolytic caps can pose a safety hazard.

These capacitors are in power supplies and some have a resistor across them, called a bleed resistor, to discharge the cap after power is switched off.

If a bleed resistor is not present the cap can retain a charge after the equipment is unplugged. How to discharge a capacitor Do not use a screwdriver to short between the terminals as this will damage the capacitor internally and the screwdriver.

Use a 1k 3watt or 5watt resistor on jumper leads and keep them connected for a few seconds to fully discharge the electro. Test it with a voltmeter to make sure all the energy has been removed. Before testing any capacitors, especially electrolytics, you should look to see if any are damaged, overheated or leaking. Swelling at the top of an electrolytic indicates heating and pressure inside the case and will result in drying out of the electrolyte. Any hot or warm electrolytic indicates leakage and ceramic capacitors with portions missing indicates something has gone wrong.

A short-circuit within the capacitor 2. Capacitor values above 1u. You can test capacitors in-circuit for short-circuits. Use the x1 ohms range. To test a capacitor for leakage, you need to remove it or at least one lead must be removed.

Use the x10k range on an analogue or digital multimeter. For values above 1u you can determine if the capacitor is charging by using an analogue meter. The needle will initially move across the scale to indicate the cap is charging, then go to "no deflection.

You can reverse the probes to see if the needle moves in the opposite direction. This indicates it has been charged. Values below 1u will not respond to charging and the needle will not deflect. This does not work with a digital meter as the resistance range does not output any current and the electrolytic does not charge. Rather than spending money on a capacitance meter, it is cheaper to replace any suspect capacitor or electrolytic.

Capacitors can produce very unusual faults and no piece of test equipment is going to detect the problem.

In most cases, it is a simple matter to solder another capacitor across the suspect component and view or listen to the result. This saves all the worry of removing the component and testing it with equipment that cannot possibly give you an accurate reading when the full voltage and current is not present. You are fooling yourself. If the Test Equipment says the component is ok, you will look somewhere else and waste a lot of time.

It Starts with Food: Discover the Whole30 and Change Your Life in Unexpected Ways

Here is a simple circuit that can be added to your meter to read capacitor values from 10p to 10u. A capacitor may be slightly important in a circuit or it might be extremely critical. A capacitor just doesn't have a "value of capacitance. This is due to the way it is constructed. Some capacitors are simply plates of metal film while others are wound in a coil.

Electronics repair ebook download free

Some capacitors are large while others are small. They all react differently when the voltage fluctuates. Not only this, but some capacitors are very stable and all these features go into the decision for the type of capacitor to use. You can completely destroy the operation of a circuit by selecting the wrong type of capacitor. No capacitor is perfect and when it gets charged or discharged, it appears to have a small value of resistance in series with the value of capacitance.

This effectively makes the capacitor slightly slower to charge and discharge. We cannot go into the theory on selecting a capacitor as it would be larger than this eBook so the only solution is to replace a capacitor with an identical type. However if you get more than one repair with identical faults, you should ask other technicians if the original capacitor comes from a faulty batch.

The author has fixed TV's and fax machines where the capacitors have been inferior and alternate types have solved the problem. Some capacitor are suitable for high frequencies, others for low frequencies.

Open circuit in both directions. Low resistance in both directions. Breakdown under load. It will not allow any current to flow. Thus the needle will not move. This position represents the voltage drop across the junction of the diode and is NOT a resistance value. If you change the resistance range, the needle will move to a slightly different position due to the resistances inside the meter.

This indicates the diode is not faulty. The needle will swing to a slightly different position for a "normal diode" compared to a Schottky diode. This is due to the different junction voltage drops. However we are only testing the diode at very low voltage and it may break-down when fitted to a circuit due to a higher voltage being present or due to a high current flowing.

The best thing to do with a "suspect" diode is to replace it. This is because a diode has a number of characteristics that cannot be tested with simple equipment. Some diodes have a fast recovery for use in high frequency circuits. They conduct very quickly and turn off very quickly so the waveform is processed accurately and efficiently.

If the diode is replaced with an ordinary diode, it will heat up as does not have the high-speed characteristic. Other diodes have a low drop across them and if an ordinary is used, it will heat up. Most diodes fail by going: This can be detected by a low resistance x1 or x10 Ohms range in both directions. To locate this fault, place an identical diode across the diode being tested. A leaky diode can be detected by a low reading in one direction and a slight reading the other direction.

However this type of fault can only be detected when the circuit is working. The output of the circuit will be low and sometimes the diode heats up more than normal.

A diode can go open under full load conditions and perform intermittently. Diodes come in pairs in surface-mount packages and 4 diodes can be found in a bridge. They are also available in pairs that look like a 3-leaded transistor. The line on the end of the body of a diode indicates the cathode and you cannot say "this is the positive lead.

The cathode is defined as the electrode or lead through which an electric current flows out of a device. The following diagrams show different types of diodes: Suppose you touch both wires.

You will get a shock. The neutral is connected to an earth wire or rod driven into the ground or connected to a water pipe at the point where the electricity enters the premises and you do not get a shock from the NEUTRAL.

You never get a v shock. It is a v shock. In other words, if you touch the two wires at a particular instant, you would get a POSITIVE v shock and at another instant you would get a negative v shock. This is shown in the diagram below. We now transfer this concept to the output of a transformer. The diagram shows an AC waveform on the output of the secondary. The bottom lead is called "zero volts. The diode only conducts when the voltage is "above zero" actually when it is 0.

This is shown on the output of the Power Diode. Only the positive peaks or the positive parts of the waveform appear on the output and this is called "pulsing DC. We have used it to describe how the diode works.


The electrolytics charge during the peaks and deliver energy when the diode is not delivering current. This is how the output becomes a steady DC voltage.

The signal that it squelches is a voltage that is in the opposite direction to the "supply voltage" and is produced by the collapsing of a magnetic field. Whenever a magnetic filed collapses, it produces a voltage in the winding that is opposite to the supply voltage and can be much higher.

This is the principle of a flyback circuit or EHT circuit. The high voltage comes from the transformer. The diode is placed so that the signal passes through it and less than 0. A damper diode can be placed across the coil of a relay, incorporated into a transistor or FET or placed across a winding of a flyback transformer to protect the driving transistor or FET.

It does not have to be a high-voltage diode as the high voltage in the circuit is being absorbed by the diode. When reading in the LOW direction, the needle will swing nearly full scale and the reading is not a resistance-value but a reflection of the characteristic voltage drop across the junction of the diode.

As we mentioned before, a resistance reading is really a voltage reading and the meter is measuring the voltage of the battery minus the voltage-drop across the diode. Since Silicon, Germanium and Schottky Diodes have slightly different characteristic voltage drops across the junction, you will get a slightly different reading on the scale.

This does not represent one diode being better than the other or capable of handling a higher current or any other feature. The quickest, easiest and cheapest way to find, fix and solve a problem caused by a faulty diode is to replace it. There is no piece of test equipment capable of testing a diode fully, and the circuit you are working on is actually the best piece of test equipment as it is identifying the fault UNDER LOAD.

Using this, a silicon diode should read a voltage drop between 0. For a germanium diode, the reading will be lower, around 0.

The LED does not emit light when it is revered-biased. The light produced by a LED can be visible, such as red, green, yellow or white. They are used in remote controls and to see if they are working, you need to point a digital camera at the LED and view the picture on the camera screen.

An LED needs about 2v - 3. The simplest way to deliver the exact voltage is to have a supply that is higher than needed and include a voltage-dropping resistor. DIY Door Alarm for shed, garage etc. Need Electrolytic capacitors? Try HERE. A Beginner's Guide to Electronics - eBook. Are you interested in an on-line Electronics Course?

Click HERE for info. A Beginner's Guide Part 2 - Hobby circuits for beginners. Can be used with iPod etc. A great learning experience with something really useful to show for it when completed! By popular request this eBook has been written to explain the most basic uses of a multimeter with extensive use of photographs to show the methods in detail. There's nothing complicated in this eBook.

It sticks to simple activities like checking batteries, resistors, diodes, fuses and capacitors; measuring voltage and current. Multimeters are cheap and simple to use. Why not buy one now?

Stash it away until it's needed.

Ebook download electronics repair free

Impress your spouse, kids and neighbours with your ability to track down faults. The eBook gives lots of non-specific advice about avoiding problems, about getting it repaired if it does go wrong and, if that proves not to be cost-effective, advice on buying a new TV. Read More Looking for the cheapest? Read this first. It could save you money. More info This guide describes a simple alarm system that you can wire up easily to protect one or more doors and windows.

Explanation of how it works, special considerations and where to get the parts. These notes were written a few years ago but the points considered remain valid today. They don't contain hard and fast "rules" but attempt to make the designer think logically about his design. Of course, there are some contentious points, which are bound to raise comments such as "Why should I change. I've always done it in such-and-such a way?