How to do in circuit testing of capacitors and resistors

I am looking for recommendations on the best way to do in circuit testing of capacitors and resistors.

I’ve read about ESR meters but cannot find any quality ones online.

I’ve also read you can use a scope and a function generator.

I’m really looking for something we can use when diagnosing and refurbishing a lot of the same board. Quick and repeatable is more important than customization in my case.

I’ve also seen some smart tweezers but it’s unclear if they really do in circuit.

Anyone have experience with any of these and can make a recommendation?

It depends a lot on what the rest of the circuit is, since other components can interfere with testing. I’ve spent the last 20+ years of my electronics career in test and failure analysis, and it is often much easier and accurate to test components based on operational readings. Good in-circuit testing can often compensate for stray current paths, but at other times its nearly impossible (such as when these parts are in parallel with reactive components or low values of resistance).

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Yes, I agree that it depends a lot on what the circuit looks like. I do a lot of trouble shooting and I use a BK Precision 885 LCR meter that has the ESR function. I don’t think that model is available anymore though. It allows you to set the test voltage to different levels. One level is 50 mV. This is supposed to be a level that will not forward bias semiconductors. For in circuit testing that is something you need to have. Even with that there are times when the circuit that the component is in will have affects on the readings you get. I think that having a good knowledge of what readings are in a good circuit and then comparing that to a questionable one is what you will have to do.

Agreed with the other two. It depends on the circuit it is in. Most meters, particularly capacitance meters and testers will be completely errant with any other parts interacting with them. Also IC and microcontroller i/o in particular can introduce non linear impedance that can confuse things. Past that if you have to do in circuit testing waveform analysis compared to a known good unit is the best for in production testing. If you absolutely must do an individual component test you must analyze the rest of the surrounding circuit and develop a test condition and apparatus that will yield useful results. These become little engineering projects unto themselves and no two situations are ever the same it would seem.

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