best meter to read esr and cap value in circuit

[mattstolte]

I'm trying to find a easy way to read value and esr in Same meter in circuit is this possible and what's cheapest meter or anybody have any fast suggestions on getting this done. Like for example if you wanna check caps on a main board or power supply. I dont really wanna have to take out every one

[budm]

Re: best meter to read esr and cap value in circuit

"I'm trying to find a easy way to read value and ESR in Same meter in circuit is this possible' Not that I know of since you can have a bunch of caps connected in parallel, same thing is applied to parallel 3~4 0.1 Ohms resistors in parallel, will your Ohm meter tell you which one is bad when you measure them in the circuit. Try that with your Ohm meter.

[tom66]

Re: best meter to read esr and cap value in circuit

Generally in circuit readings are unreliable. Some meters can measure capacitance in circuit but I'm not aware of any reliable ways to measure ESR in circuit. ESR measurement relies on measuring small voltage drops caused by small impedances; resistors and inductors in the same circuit can cause false readings.

[Spork Schivago]

Re: best meter to read esr and cap value in circuit

I'm trying to find a easy way to read value and esr in Same meter in circuit is this possible and what's cheapest meter or anybody have any fast suggestions on getting this done. Like for example if you wanna check caps on a main board or power supply. I dont really wanna have to take out every one

I like the Peak Atlas ESR Plus (ESR70) but for the reasons that other people have already stated, it's not very good at reading caps in circuit. It can give successful readings for certain ones (probably ones in series vs parallel) but just to be safe, I always remove them.

Correct me if I'm wrong here, but you could always just remove one lead instead of pulling the whole cap, right? I know it isn't the best option, but perhaps it could cut your work time in half?

Anyway, here's a link to their site's test instruments:
http://www.peakelec.co.uk/acatalog/jz_instruments.html

And here's a link to the ESR70:
http://www.peakelec.co.uk/acatalog/jz_esr70.html

[stj]

Re: best meter to read esr and cap value in circuit

Correct me if I'm wrong here, but you could always just remove one lead instead of pulling the whole cap, right?

yes, that's the best way to test diodes too.

[CapLeaker]

Re: best meter to read esr and cap value in circuit

Look up LCR meter. Uni-T, Agilent, B&K and others make them too.

[Spork Schivago]

Re: best meter to read esr and cap value in circuit

Look up LCR meter. Uni-T, Agilent, B&K and others make them too.

Sorry to hijack the thread a little, but I've seen LCR meters for sale before. Peak Atlas sells one as well. What exactly are they for? I always thought for some reason, they where for measuring coil type stuff. Am I wrong about that? Thanks.

[tom66]

Re: best meter to read esr and cap value in circuit

They measure L, C, and R. L is Inductance (as "I" was taken for current), C for Capacitance and R for Resistance.

The measurement can be taken in series (L+C+R) which is useful for measuring the ESR of a capacitor, or it can be taken in parallel (L || C || R) which is not particularly useful for capacitors but has uses in transformer analysis and test.

[SteveNielsen]

Re: best meter to read esr and cap value in circuit

If a part tests weird in a circuit then disconnect it and measure it again to be sure. Or cut to the chase and just test it out of circuit to start with.

[CapLeaker]

Re: best meter to read esr and cap value in circuit

Tom66 explained it just nicely. I use an LCR meter for example. You are kind of right with the measuring inductors (L) but it does capacitance, DCR and ESR (C), and resistance (R) too. Depending on money, they have different ranges of frequencies, in which a broader size of caps can be measured.

[diif]

Re: best meter to read esr and cap value in circuit

Sorry to hijack the thread a little, but I've seen LCR meters for sale before. Peak Atlas sells one as well. What exactly are they for? I always thought for some reason, they where for measuring coil type stuff. Am I wrong about that? Thanks.

I use my LCR40 to measure low value capacitance that the ESR60 can't measure and to lazily measure resistance. I mainly got it as it came cheap with the DCA55.

[mattstolte]

Re: best meter to read esr and cap value in circuit

so a lcr can measure cap value and esr in circuit?

[budm]

Re: best meter to read esr and cap value in circuit

so a lcr can measure cap value and esr in circuit?

, No, the LCR can do more than just for testing caps, it can test inductor and resitstor. Component should be tested off the board or lift one leg off the board.
LCR meter:

[Spork Schivago]

Re: best meter to read esr and cap value in circuit

Thanks for all the explanations for what an LCR meter does. I've read a little bit about inductance and I'm still not 100% certain what it means. So basically, if someone can already measure ESR and capacitance and resistance, the only reason to get an LCR meter would be for measuring inductance?

[mattstolte]

Re: best meter to read esr and cap value in circuit

Well I guess what I'm looking for is a meter that reads value and esr then. Also what you guys think of them ones on ebay that automatically read npn also