Computer Grade capacitor testing

[microfarads]

Hi --- I have hundreds of large, high capacitance computer grade caps -- what equipment do i need to do basic tests to see if they are in good working order?

Thank you!

[Uranium-235]

Re: Computer Grade capacitor testing

ESR meter. it puts a 100Khz signal into the cap and reads the impedance

[microfarads]

Re: Computer Grade capacitor testing

Thank you uranium - much appreciated

so by using an ESR meter and applying the 10khz signal into the cap -- it'll tell me if the capacitance of the cap?

sorry, i'm trying to learn ---

[mariushm]

Re: Computer Grade capacitor testing

The capacity can be told by a regular multimeter and it's generally pointless to measure it, as capacitors are from the factory rated for +/-20% their capacity value and also the capacity will vary a bit depending how they're used.
To put it simply, a capacitor will have a certain capacity value when tested with the multimeter, and a different value when on a motherboard or a power supply.

The ESR value can only be "measured" by an esr meter. And it's 100 kHz frequency... the esr meter will apply a 100kHz frequency something into the capacitor and measure how the capacitor reacts to that.

The value is not a Good or Bad result... the value will depend on the series of a capacitor and its purpose.
On general purpose capacitors, it's normal for the value to be a bit higher, on capacitors usually used in power supply, motherboards etc the capacitor series used on those usually have a very low esr value.
The value also varies with the capacity and the size (diameter and height) of the capacitor.

[kc8adu]

Re: Computer Grade capacitor testing

you may need to reform them to get the leakage in spec to test.
otherwise measure esr and compare to specs.

[ratdude747]

Re: Computer Grade capacitor testing

Moved out of FAQ.

[Agent24]

Re: Computer Grade capacitor testing

Ultimately you should test their ESR, Capacitance and Leakage current to ensure all are within specification. You can find out what these should be in the datasheets.

But high leakage is more likely in NOS (New Old Stock) and ESR problems are from ones that are just plain crap.