Learn The Easy Way To Test Electronic Components and Perform Electronics The Good News Is Once You Have Completed Reading My Ebook And Start. Preview Of The Ebook. Testing Electronic. Components. Brought to you by Jestine Yong echecs16.info Free pdf testing electronic components. echecs16.info Testing Electronic Components Ebook - The Best Review Guide Fix. How to get FREE electronic parts.
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Testing Electronic. Components. Brought to you by Jestine Yong http://www. echecs16.info echecs16.info This is an eBook writing by Colin Mitchell about test electronic components. http:// echecs16.info is Colin. Full text of "Testing Electronic Components by Colin Mitchell". See other formats. This eBook shows you how to TEST COMPONENTS. To do this you need.
That means no need to remove the components and directly test it with meter. Yes of course in some cases you can test the non polar cap on board but most of the time it was not accurate when you test it on board using the digital capacitance meter. Even in resistors too, if you have experience in electronic repair you would know if a resistor value is good or bad if you test in on board but somehow i prefer to test resistor off board which i found it to be more accurate than checking it on board. Similarly i have a question whether i can use the blue ring tester to test the primary winding of flyback transformer on board or not. If you are a seasoned electronic repairer then i guess you have no problem using that meter to test the winding on board because from your many repair experience you already should know how was the reading like. However if you are a beginner i suggest that you test it off board be it in flyback transformer or any other electronic components because as time past you will surely know as to which components that you should check on board or off board.
We will start with resistor first. Do you know that you can actually check a resistor while it still on board? This is true especially when the test voltage output from your digital meter is less than 0. If it is more than 0.
Another thing you need to know is that if the resistor that you are checking on board parallel with another resistor, you will not get an exact reading. If you get 0 ohms, this is very obvious that the resistor have open circuit. What if you get 2. This resistor is either open or has gone up in value.
Other circuit components cannot possibly increase the value of a resistor; any back circuit could only make the resistance reading lower! Light emitting diodes or LED is very simple to check. Just connect your analog meter probe to the pins of LED and set your meter to X1 ohm. If there is no light from the LED, just change the polarity of the probes. You can check LED while it is still in circuit. First you must know what the part numbers of the voltage regulator are, and then you read the specification and locate the input and output voltage and pins.
For example, the general type of voltage regulator starts with the part numbers like , , and etc. From the spec you would know that pin one is input, pin 2 is ground and pin 3 is output.
If there is input voltage to the voltage regulator and no or low output voltage, suspect the voltage regulator itself faulty or something along the output line that dragged down the output voltage. Do you still remember from my previous article that voltage regulator can breakdown when under full load? Since the voltage regulator is easily available and cheap, just direct replace it and retest the equipment or recheck again the output voltage.
Whenever there is any power failure fuse totally blown into dark color one will always suspect the power FET has gave way. Usually we would use the black probe set to X 1 ohms and place it to the center pin drain and the red probe to the gate and the source pin.
This is the same way when we want to check HOT on board. If there is a reading, chances are high that the FET has developed a short circuit. But you also have to remember that a shorted bridge rectifier may cause the power FET to have reading when check with the analog meter while it still on board. Checking variable resistor VR on board is not that accurate because of the back circuit besides some VR have their resistance code printed so small at the bottom of the VR.
The best is still removing it out from the circuit and test it with an analog meter. Any erratic reading can be easily seen from the analog meter panel compares to using digital meter. Inductor or coil testing can be done on board without removing the coil out from the circuit board.
If a coil has less loops small coil , then we can just direct measure it with our normal ohmmeter. A small coil is just like a wire or a jumper and it rarely become defective although it has some inductance value in it.
The meter that I use to check the bigger coils is the Dick smith flyback tester. You can check the coils while it is still in the circuit. Checking horizontal output transistor is so easy and you can check it on board. Set your analog meter to X 1 ohm and place the black probe to the center pin collector of the HOT and the red probe to base and emitter. It should not register any reading. If there is a reading, most probably the HOT has developed a short circuit.
Some HOT in certain Monitor designs are difficult to open you have to remove the whole board in order to unscrew the HOT so to save time follow the example above. You can only test it with a special type of coil meter or the dick smith flyback tester.
You can check the primary winding of the SMPT on board without removing it out with the flyback tester. Assuming when an equipment came in with a blown fuse fuse became dark , this sign shows that the equipment might have a major short circuit somewhere in the circuit mainly power supply area.
Using your analog meter set to X 1 ohms to check on the bridge rectifier on board you can easily tell if the any of the bridge diodes have shorted. Checking zener diodes, you have to remove one lead from the board. Before you check on any zener diodes, you first need to identify what is the voltage of the zener diodes. Refer to semiconductor data book for any codes printed on the body of zener diodes.
Once you know the zener diode voltage, by using again analog meter set to X 10 K ohm range, you will quickly determine if the zener diode is faulty or not.
Any zener diodes from 2. You can check also zener diode on board if only the zener diode developed a direct short circuit which is easily measured with an analog meter set to X 1 ohm range. Remember to replace zener diode only with the same voltage and for the wattage, it can be the same or a little bit higher. There are two different ways to test capacitors.
One for the electrolytic capacitor and the other one for the non-polar or the ceramic type capacitor that do not have polarity. I will start explaining the electrolytic capacitor first. I believe many of you already own the ESR meter for testing electrolytic capacitor on board. There are many types of ESR meters in the market nowadays.
No matter what ESR meter you use, the result you get will be the same which is checking the ESR Ohm of the electrolytic capacitor while it still on board. I myself also use ESR meter to check for bad e-caps everyday. Without one I will have a hard way to find the defective E-caps. If you check on the Monitor heater circuit, it would not give you an accurate reading because the heater line is eventually go to cold ground through the filament inside the CRT tube.
In other words you are actually measuring the low resistance winding of the filament. The same case also happen if you try to check any E-caps that have a low ohm resistor parallel with the e-caps that you want to check. Another good example would be the secondary output lines. Have you ever come across secondary output lines that have few electrolytic capacitors along the same line?
In fact those are not just examples; it was the real life experienced that I had encountered as electronic repairer. Do not worry about the above explanations as there are solutions for it. Otherwise you would not get an accurate result from your ESR meter. One more advice, never check the e-caps with a digital capacitance meter as a bad e-cap the meter will tell you it is good and you will be wasting of your precious time trying to find out the real fault in the equipment.
Next is the non polarity capacitor, you have to desolder on lead in order to test the capacitance. After you have confirmed that the capacitance is good you need to perform another test which is using analog meter set to X 10 k ohm to check for any short circuit between the internal plates.
If the capacitor that you want to check rated several hundreds volts then I guess you have to use an insulation tester to check it. In other words, your analog meter does not have the feature that can pump in hundreds of volt to a non-polarity capacitor. Just let the insulation tester do the job. The last component that I want to share in this article is the bipolar transistor. You can actually check transistor on board without removing it to speed up your repair work. First you must know as which types of the transistor that you want to measure belong to.
Assuming you have checked that the transistor is NPN type, then desolder the base and the collector pin. Do not desolder the emitter pin. Place your analog meter black probe to base meter set to X 1 ohm and the red probe to collector and then to the emitter pin. It should give two similar reading but not shorted readings!
Now set your meter to X 10 K ohms and place your meter probes to the collector and the emitter pins either way. Some good transistors can show no reading on both ways while some will show only one reading but not shorted reading.
If you get two readings then the transistor is considered bad and need replacement. Hands on practice only make us perfect and the result would be you can check any electronic components in the shortest time and accurate too. However, you have to remember that electronic components can test good but breakdown when under full load. Your experience will tell you if the components need a direct replacement.
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