This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
electronic_component_testing_cheatsheet [2022/02/07 12:35] sausage [Transformers] |
electronic_component_testing_cheatsheet [2022/02/23 12:35] sausage |
||
---|---|---|---|
Line 7: | Line 7: | ||
{{:component-cheatsheet:anmeg-an8009.jpg?direct&200|}}{{:component-cheatsheet:gm328.jpg?direct&300|}} | {{:component-cheatsheet:anmeg-an8009.jpg?direct&200|}}{{:component-cheatsheet:gm328.jpg?direct&300|}} | ||
+ | <WRAP center round tip 80%> | ||
One last thing: //Any values shown in the illustrations are vague examples only//. | One last thing: //Any values shown in the illustrations are vague examples only//. | ||
+ | </WRAP> | ||
+ | |||
Line 28: | Line 31: | ||
---- | ---- | ||
- | ===== Switches (TODO) ===== | + | ===== Switches ===== |
- | You can never under-rate the testing of a switch. Switches can break, it's continutity can flucuate. A switch can be normally open (the most common type) or normally closed. | + | You can never under-rate the testing of a switch. Switches can break: it's continutity can fluctuate. A switch can be ''normally open'' (the most common type) or ''normally closed''. |
+ | |||
+ | {{ :component-cheatsheet:switch-testing.png?direct&400 |}} | ||
The continuity tester on your multimeter is the mode to use. | The continuity tester on your multimeter is the mode to use. | ||
- | An interest break in a recent dishwasher repair, I had a microswitch that would click when pressed... it sounded like it was activated, but unless you pressed it further, there was no continutity. Needed replacing. | + | - If it's a normally open switch, ensure there is only continutity when it is pressed. |
+ | - If it's a normally closed switch, ensure there only continutity when it is not pressed. | ||
+ | An example of an interesting switch break [[vulcan_dishlex_milano_dishwasher_repair|in a recent dishwasher repair]]: with a microswitch that would click when pressed... it sounded like it was activated, but unless you pressed it further, there was no continutity. Needed replacing. | ||
+ | ---- | ||
===== Capacitors ===== | ===== Capacitors ===== | ||
Line 66: | Line 74: | ||
===== Inductors ===== | ===== Inductors ===== | ||
- | {{:component-cheatsheet:inductor-testing.png?direct&200 |}}Using the resistor setting, put the probes on either end of the inductor. There should be an initial reading that quickly drops to 0Ω. This means the inductor is OK. | + | {{:component-cheatsheet:inductor-testing.png?direct&150 |}}Using the resistor setting, put the probes on either end of the inductor. There should be an initial reading that quickly drops to 0Ω. This means the inductor is OK. |
If you get OL, you have a break in the inductor and it is bad. | If you get OL, you have a break in the inductor and it is bad. | ||
Line 84: | Line 92: | ||
You can also test for a short by using the resistance setting. If you get a very low reading around 0.01Ω etc in either direction, you have a shorted out diode. | You can also test for a short by using the resistance setting. If you get a very low reading around 0.01Ω etc in either direction, you have a shorted out diode. | ||
- | Testing LEDs (which are diodes too) is fun with a multimeter because you can see them light up in the correct direction. | + | {{ :component-cheatsheet:led-testing.png?direct |}} |
+ | |||
+ | Testing LEDs (which are diodes too) is fun with a multimeter because you can see them light up with the correct orientation. | ||
Sometimes you can get false positives with parallel components, so remove the diode from the board to test if in doubt. | Sometimes you can get false positives with parallel components, so remove the diode from the board to test if in doubt. | ||
Line 189: | Line 199: | ||
===== Relays ===== | ===== Relays ===== | ||
- | {{ :component-cheatsheet:relays.jpg?direct&400 |}} | + | Relays can vary the amount of pins they have. Two relay configurations that are reasonably common are covered. |
- | Relays can vary the amount of pins they have. I'll cover the relays that have two pairs of pins: one as a pair that are evenly place next to each other, and another that are offset from each other. This can vary wildly so I'll only cover this configuration. | + | {{ :component-cheatsheet:testing-relay-four-terminal.png?direct&600 |}} |
- | The side with two even pins are connected with a coil. | + | This four pin relay has a pair of pins equally spaced, which is the voltage and ground pins. These pins have a coil between them. Putting DC voltage across this will energise the coil and either connect or disconnect one or more pairs of switch pins to allow another circuit to flow. |
- | The other two pins are the switch. | + | - Measure the resistance across the voltage pins. The result is somewhere in the hundreds of Ohms. |
+ | - Measure the switch pins without any voltage across the voltage pins. In the case of a ''Normally Open'' relay, there should be no connection. | ||
+ | - Measure the switch pins without voltage across the voltage pins. In the case of a ''Normally Open'' relay, there will be continuity. | ||
- | If you measure with your resistance setting on the coil pins, you should receive a reading. This means the coil is fine. | + | {{ :component-cheatsheet:testing-relay-five-terminal.png?direct&900 |}} |
- | If you measure the switch side of the relay with continuity, there should be no connection. | + | In this five pin relay example, there is a pair of voltage pins, a common ground that then connects to both a ''Normally Open'' pin and a ''Normally Closed'' pin. |
+ | |||
+ | - Measure the resistance across the voltage pins. The result is somewhere in the hundreds of Ohms. | ||
+ | - Measure between ''Common Ground'' and the ''Normally Open'' pins without any voltage across the voltage pins. There should be no connection. | ||
+ | - Measure between ''Common Ground'' and the ''Normally Closed'' pins without any voltage across the voltage pins. There should be continuity. | ||
+ | - Measure between ''Common Ground'' and the ''Normally Open'' pins with voltage across the voltage pins. There should be continuity. | ||
+ | - Measure between ''Common Ground'' and the ''Normally Closed'' pins with voltage across the voltage pins. There should be no connection. | ||
+ | |||
+ | A great fresher on many types of relays can be found here: [[https://projectiot123.com/2020/03/28/what-is-relay | What is relay]] | ||
---- | ---- | ||
Line 230: | Line 250: | ||
- https://www.youtube.com/watch?v=QqWM3pBirzM | - https://www.youtube.com/watch?v=QqWM3pBirzM | ||
- https://www.youtube.com/watch?v=D0OQvuux6CE | - https://www.youtube.com/watch?v=D0OQvuux6CE | ||
+ | |||
+ | ---- | ||
+ | |||
+ | ===== Varistors ===== | ||
+ | |||
+ | Ok, these suckers are tricky to test. They look like a capacitor, or a thermistor, but are nothing like them. Rather than try and explain how to tell them apart, you are better off using this [[http://epicbeardquest.blogspot.com/2015/03/is-that-varistor-or-capacitor.html | excellent identification guide]]. | ||
+ | |||
+ | Varistors do not test like a resistor, so the resistance measurement will show no connection or continuity. | ||
+ | |||
+ | {{ :component-cheatsheet:varistor-testing.png?direct |}} | ||
+ | |||
+ | You can test them like a capacitor using a multimeter or GM-328. Don't expect a value that looks like something on the packaging. Just know if you get a low (pF) range value, you have some confidence that you have a working part. Again, check the guide above to get an appreciation of the expected values. | ||
+ | |||
+ | In my example is a TVR 10561. The 10 is component 10mm wide. The 561 is a 560V tolerant unit. If I mistook the 561 as a 561pF part, it will actually test at around 220pF mark which is roughly half, which lines up with the guide above. | ||
+ | |||
+ | ---- | ||
===== Conclusion ===== | ===== Conclusion ===== | ||
- | This article is likely to expand over time. If this is handy for you, please pass it along to friends and let me know. I love to hear from other repairers. | + | This article is likely to expand over time. If this is handy for you, please pass it along to friends. I love to hear from other repairers, if you spot anything wrong, please let me know. |