EEVblog 1474 - Can You Measure Capacitors IN Circuit?

Can you measure capacitors in-circuit with an LCR meter?

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#ElectronicsCreators #Measurement #Capacitors

[roberthurley]

In circuit testing (passive and active) combined with a good understanding of the circuits purpose and together with a creative mind and coupled with experience can yield excellent results. I have to say you have done an excellent job putting this all together.

[PeteWord]

This was informative to me .. I have been thinking about purchasing an ESR meter to troubleshoot my TV. I watched both videos .. I like how you split them up. Thanks Dave!

[aazjo]

On the other video I was going to ask what kind of difference the frequency makes, but this explained it perfectly. Thanks Dave for educating us.

[samh]

Awesome demonstration of how an LCR meter works and how to use it. The interlude was great, like a college lecture + lab

[TheDefpom]

@5:00 the short lead cable set is also a 4 wire measurement.

[donepearce]

I have a little yellow kidney-shaped LCR meter (Atlas LCR40.) and it only has automatic mode. EG, when measuring a cap it starts with DC. Big electrolytics get measured by rise time. If the cap is smaller it will move on to a 200Hz sine wave. After that it will try 16kHz, and finally 200kHz for the smallest caps. It applies these test tones in bursts, and the final measurement is made with an average of about twenty bursts.

[MatthewAlbert-zoonotique]

My dad was an electronics technician for 30 years and imparted to me an appreciation for ESR meters. As an industrial electrician I occasionally have use for one too, and keep one in my desk.

I've been eyeing his old Creative Electronics ESR meter, but he still won't part with it. The analog needle deflection is great for quick go/no go checks.

[Satchmoeddie]

My empirical experience with LCRs is you can measure over 90% of the e-lytic caps in circuit. Mine is about 45 years old but it's a really good old bench LCR meter. I can run down to 1mV & up to 1500mV.

[aduedc]

Also do not forget to discharge the in circuit caps, before measurement; otherwise, it could damage your test equipment and might shock you.

[cwang]

As an onsite electrician that insists on repairing every electronic circuit that fails, I found this interesting. Wasn't familiar with this technique, might have to buy the meter!

[Stefan_Payne]

Well, you start with one Video, but end with 3 - and thats how you make your best works!
Keep up the good work!

[lcr-reader]

During the presentation, I observed that you had the LCR-Reader-MPA on your desk; however, you did not utilize it. I would like to point out that the LCR-Reader-MPA offers a convenient feature - it can indicate the presence of a p-n junction in parallel to the measured component. When a p-n junction is detected, the device automatically switches to a 0.1 V peak-to-peak signal level. This capability greatly simplifies in-circuit measurements and can be quite useful.

[hullinstruments]

In circuit ESR testing cannot be understated. The “EDS-88a” is used daily in my lab.

But it’s really important to have A bit of experience & understanding on what to expect with different circuits and topologies.
Blindly going over a bunch of faulty boards with in circuit ESR testing won’t help unless you have a bit of experience and understanding of what to look for in certain situations. But even beginners and hobbyists can learn what to look for really quickly, and even some of the cheaper sub $50 in circuit ESR testers are pretty good believe it or not.

I’ve got over a dozen different “in circuit“ ESR testers, even a couple of really nice analog movement types. I just enjoy collecting various types of “quirky“ Devices. Like the offbeat Devices and equipment commonly sold in the back of electronics magazines from the 70s-90’s… “One little device that will solve all your problems.... without spending a fortune“. 😂

Just quirky and interesting pieces of test equipment like that. Some of them obviously turned out to be very useful, or at least informative and gave me ideas for other test equipment designs.

I use them constantly in my small and HUMBLE metrology lab. I do component level board repair for industrial clients, and specialize in metrology/test gear stuff for other small labs and manufacturers. Rarely do I need the the fancy Sencore “ReZolver” LC103. However I think high end capacitor analyzers and leakage testers are more important and needed by folks working with vintage equipment. If I’m questioning the integrity and performance of a capacitor enough to remove it from circuit, and check it on the LC103 or other leakage tester… Then I’m replacing the bastard and not giving a second thought.

However I understand when dealing with old and vintage equipment … It can be a different situation and you only want to replace what is necessary. Also needing to compare specs and performance of various capacitor types. But I don’t work with vintage gear unless it’s just a coincidence to find an old piece of test equipment still in use Buy one of my clients.

Don’t get me wrong.... if you’re a professional and servicing labs and equipment like that… it’s a good idea to have a true capacitor analyzer. But it’s kind of similar to a semiconductor analyzer… Not something I break out unless i’m getting balls deep into a very complex project, or if working on a exotic/undocumented piece of equipment… Where manufacturers can sometimes be less than helpful.

Very interesting topic, glad to see folks not totally discounting the idea… A lot of professional folks just totally blew it off in the past. But I think it’s justifiable for a lot of full-time folks.

[dhpbear]

I'm guessing the reason you didn't find any is that high-value electrolytics are used for decoupling; rarely would they be attached to a CMOS input for example.

[Gameboygenius]

3:53 to the people I've had arguments with in the past, OL means overload, not open line. This is a perfect example of where open line just makes zero sense for a meaning of OL.

[nonsuch]

I've been doing it for years with my manual ranging LCR meter. It works well for the high value caps like you've shown. Even with the parallel resistor if it has one, that just makes it look like a leaky cap which usually doesn't affect the value but, we're not testing for leakage and you wouldn't want to do that in-circuit anyway. ESR, yes. EPR, no.👍

[artursmihelsons]

Thanks, Dave, for excellent video! 👍
This gives me a clue why my LCR meter shows, sometimes, extra more for slightly bad caps..
Never thought about connecting a scope to LCR for visualization.. Now my today's mission is to do that at lab.. 😂

[robinsattahip]

I like this kind of video, practical things I can use. I have the same problem with a cheap ESR meter, it won't zero out.

[DrFrank-xjbc]

The DE-5000 also features proper 4W Kelvin connection, so the lead resistance is compensated for. Specification indicates, that high µF values can be measured only @ low frequencies. Your agilent 1733 can do this as well.

[travised]

Dave is is truly a genius thanks again