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Troubleshooting Using Electronics Testing

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To test each component here is a short list of the components and the way they should be tested:

• Capacitors: After you have done visual checking as explained above, but you are not satisfied and want to test the capacitor, here are the steps you need to take to test it correctly:

o Put your multi-meter a couple of volts above the voltage setting for the particular capacitor you are checking. Usually this will be about 10 volts.
o At this time take the positive or red probe and place it on the positive side of the capacitor, or the side where there is no negative strip.
o Now place the negative or black probe to the negative side of the capacitor. This is usually the side with the negative strip.
o Look at the tester and see what your voltage reading is. If you look at the meter long enough you will notice that the meter reached a peak voltage and dropped slowly. If this is what you get you have a good capacitor. If you do not get these results, the capacitor is defective.

• Resistors: As with the capacitor above, if you have done your visuals and you still want to test the resistor, here are the steps you need to take:

o Make sure there is no power to the circuit before testing. This includes batteries and AC. Also, discharge any large capacitors as they may feedback voltage into the circuit.
o Take your meter and place it on the resistance (ohm) setting.
o Locate the resistor and place one probe on one end of the resistor and the other one on the other end. It does not matter which probe goes where as long as you have one on one side and the other on the other side. If you cannot get an accurate reading this way, remove one end of the resistor from the circuit and recheck it.
o Take note of the reading. Check this with the required reading. If they are the same, this resistor is good. If there is no resistance or the resistance is infinite, the resistor is bad.

• Diodes: After visual inspection, you are not certain about he reliability of the diode, here are steps you need to take to test the diode:

o Make sure there is no power to the circuit.
o Take the positive (red) lead and place it on the negative side or side with no stripe.
o Place the negative (black) lead and connect it to the positive side of the diode. You should get a reading. Now reverse the probes and you should get infinity. This means a good diode. If you get anything different, you have a bad diode.

• Transistors: To test the transistor you need to know which lead is the Emitter (E), which is the Base (B), and which one is the Collector (C). To test the transistor follow these steps:

o Place your tester on the diode setting, if it has one. If it doesn’t, you will need to use either a transistor tester or a diode tester.
o Place the positive (red) probe on the Base and the negative on the Emitter. If the transistor is an NPN type transistor, you will get a reading.
o Next, while leaving the positive probe on the Base, place the negative probe on the Collector. If the transistor is an NPN, you will get a reading.
o After you have confirmed the above tests, place the positive (red) probe on the Collector and the negative (black) probe on the Emitter. You shouldn’t get any kind of reading here. If you do get a reading, the transistor is bad. This goes for PNP transistors as well.

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