Low leakage capacitor

[fixit7]

I am trying to find info about what a low leakage capacitor is.

I read that aluminum electrolytic caps have a higher leakage rate than most other types.

How do you determine if a capacitor is low leakage?

I was looking at this one.

0.1µF 250 Volt 10% Metallized Film Capacitor Axial
Specifications

    Capacitance: 100000 pF / 100 nF / 0.1µF
    Voltage rating: 250 VDC
    Tolerance: ±10%
    Size: 14mm x 8.5mm x 4.5mm (W x H x D)
    Axial leads

[Gyro]

All Film capacitors are low leakage for normal purposes.

Where leakage is particularly important, for instance high performance, high impedance measuring equipment, then Polypropylene, Polystyrene and Teflon (PTFE) are lower leakage than Polyester/Mylar and Polycarbonate.

P.S. Insulation resistance is normally specified in the datasheet.

[bob91343]

All practical capacitors leak.  Whether leakage is considered low or not is a value judgment based on the intended use and the specifications for a particular unit.

Sometimes leakage is specified in milliamperes and sometimes as insulation resistance.  Electrolytic units are poor in this regard due to their chemical composition and structure.  Mica, paper, plastic, air, ceramic, etc. all have peculiatirites that make them desirable or not for a specific use.

Electrolytic capacitors have the additional property of polarity which limits their use.

[BravoV]

How do you determine if a capacitor is low leakage?

For sure you need to test it at the rated voltage.

Did some cap leakage measurements while ago, but my DC PSU only maxed out at 37 Volts, that was the only maximum I could test with the ad-hoc test jig I made using DMM.

For high voltage cap like yours, even using lower voltage, still you will have some clues how it compares to other more leaking cap like electrolytic, check this out -> HERE.

Hope this helps.