Measure leakage current of a capacitor

Thread Starter

Fafatata

Joined Sep 19, 2022
3
Hi,

I want to develop a circuit to measure the leakage current of a capacitor. I tought about transimpedance amplifier to do that, but it's maybe too difficult for a very low current like this one ? Do you have any suggestions ? Thank you so much :)
 

Alec_t

Joined Sep 17, 2013
13,153
Do you mean pA-fA? You would have to eliminate all other leakage current due to your measuring equipment itself, e.g. atmospheric and surface contamination leakage. Quite a challenge.
 

MisterBill2

Joined Jan 23, 2018
13,141
Bob Pease wrote a great deal about leakage currents and measuring them, and about reducing them. That information, if you can find his writings, will answer your questions better than most other folks will.
 

Ian0

Joined Aug 7, 2020
6,313
The problem you will have is that the leakage current of a piezo disc is rarely specified on the datasheet, so it is not a parameter that the manufacturer controls. That means that if you find one with a certain leakage current there is no guarantee that any others will be the same.
I‘d suggest connecting it in series with a 1M resistor across a 10V power supply and measuring the voltage across the resistor with a multimeter. That would be reasonably accurate down to 100nA. I don’t know that anything beyond that would be worthwhile.
 

MisterBill2

Joined Jan 23, 2018
13,141
Normally piezo discs are not used in an application where leakage current matters much. Or are you hoping to use it as a mechanical element somehow, with constant DC applied? What sort of application requires knowing how much leakage current there is??
Could you explain about the application where piezo disc leakage matters??
Actually, a capacitance meter that also reads the dissipation factor should allow you to compare leakage between discs.
 
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