How to test a capacitor

[Karthik rajagopal]

Hi all,
While debugging using a normal DMM I am able to measure resistance, continuity etc.. but I am not able to measure a capacitor for me to know whether it is in a good condition and even a voltage regulator. Please help me .

 

[Alec_t]

What do you mean by 'good condition'?
It is relatively easy to measure capacitance, but not so easy to measure, for example, breakdown voltage of the dielectric or to detect intermittent internal faults.

 

[Herschel Peeler]

Hi all,
While debugging using a normal DMM I am able to measure resistance, continuity etc.. but I am not able to measure a capacitor for me to know whether it is in a good condition and even a voltage regulator. Please help me .

Is it shorted? If so it's bad.
You could undo one side of larger capacitors and see if they hold a charge. Charge it up on Ohms scale. Switch to voltage and see if it held a voltage.

 

[davenn]

Is it shorted? If so it's bad.
You could undo one side of larger capacitors and see if they hold a charge. Charge it up on Ohms scale. Switch to voltage and see if it held a voltage.

that's going to be very unreliable as the cap will discharge through the meter pretty quickly

but I am not able to measure a capacitor for me

buy a DMM that has a capacitance test section on it .... they are very common these days


Dave

 

[Karthik rajagopal]

that's going to be very unreliable as the cap will discharge through the meter pretty quickly




buy a DMM that has a capacitance test section on it .... they are very common these days


Dave

Thanks for the suggestions. How to test a voltage regulator without desoldering it from the PCB ?

 

[Karthik rajagopal]

Is it shorted? If so it's bad.
You could undo one side of larger capacitors and see if they hold a charge. Charge it up on Ohms scale. Switch to voltage and see if it held a voltage.

Will it work? Will the charge in the ohms scale be enough for the capacitor to get charged?

 

[Herschel Peeler]

that's going to be very unreliable as the cap will discharge through the meter pretty quickly




buy a DMM that has a capacitance test section on it .... they are very common these days


Dave

depending on the size of the capacitor, that is true. Yes, ,buying a capacitor tester is a better idea.

 

[Karthik rajagopal]

depending on the size of the capacitor, that is true. Yes, ,buying a capacitor tester is a better idea.

Is there any specific name for the capacitor tester?

 

[Bluejets]

I just put "capacitor tester" in an Ebay search and came up with hundreds BUT you may want to go for a multimeter with a capacitor test range included. Might be more handy for other things as well at around the same cost.
Depends what range you need to test capacitors at. The specific tester may well cover a broader range.

 

[davenn]

Thanks for the suggestions. How to test a voltage regulator without desoldering it from the PCB ?

with the multimeter in the appropriate voltage range
black lead probe to the 0V (negative) and the positive probe first onto the regulator input pin, note the voltage
then move to the output pin and note the voltage ( should be whatever the regulator is spec'ed for)


Dave

 

[Herschel Peeler]

Is there any specific name for the capacitor tester?

I'm 10 years out of touch with such things. Google capacitor tester or maybe some of those here can suggest something.

 

[Karthik rajagopal]

Thank you so much guys

 

[BobK]

There are many inexpensive component testers now available on Ebay. These will test resistors, capacitors, diodes, inductors and transistors. For capacitors they will give you the capacitance as well as ESR.

Bob

 

[bsco]

get yourself a capacitor tester and an ESR tester.....the cap tester will test for rated capacitance while the ESR tester will test for Effective Series Resistance...A decent cap tester will cost around $75 and an ESR tester will be slightly more depending on where you buy it...ESR testers can also be built and there is lots of info on google and youtube about it.....

 

[Docholiday]

Get one of these below a DE-5000 on ebay. Inhave one of these and a dedicated bench one that I paid $$$$$$ for. I use my De-5000 99% of the time. Compared to Agilent its pretty well spot on.

http://www.ebay.com/itm/DER-EE-DE-5...803373?hash=item41aaf1202d:g:b4oAAOSwwE5WUtPM

 

[SPLatMan]

As BobK suggested, there are cheap, effective component testers based on an open source design by a chap in Germany. I got one a couple of weeks ago and it's instantly become my go-to instrument for checking transistors, diodes, caps, resistors. I just took a pic for you with it testing a relay coil. I bought mine from BangGood. http://www.banggood.com/MK-328-Tran...Resistor-Meter-LCR-NPN-PNP-MOS-p-1010347.html but I'm sure you can get them elsewhere.

 

[tilup367]

Hi all,
While debugging using a normal DMM I am able to measure resistance, continuity etc.. but I am not able to measure a capacitor for me to know whether it is in a good condition and even a voltage regulator. Please help me .

So, capacitor just like resistor have a acceptable tolerance. So let said a 10 uF capacitor with +-10% mean the capacitor is good if his capacitance is between 9 and 11 uF. Then, if your capacitors are "in-circuit" you MUST unsoldered them because other capacitor or inductor or even resitance may false your reading.

 

[Gie]

I'm 10 years out of touch with such things. Google capacitor tester or maybe some of those here can suggest something.

For capacitor tester you can used or buy capacitance meter ot check those leakage or short or u can try this web :www.jestingyong.com.

 

[Kaj Lonnqvist]

Hi all,
While debugging using a normal DMM I am able to measure resistance, continuity etc.. but I am not able to measure a capacitor for me to know whether it is in a good condition and even a voltage regulator. Please help me .

Guess the best is to buy a cheap DVM with capacitor testing included. Otherwise you must use an AC source (e.g. a tone generator) and connect the capacitor to test i neries with a known good capacitor, maybe in a Wheatstone bridge configuration.

 

[poor mystic]

Hi
Internal leakage in electrolytics, at rated voltage or below, can cause problems. These problems often appear in the circuit as noise.