/diy/ - Do It Yourself

>>1172204
Small enough to ignore any leakage current? That would be nice, but surely you could just run any smaller cap across a voltage source and measure the current to figure out the leakage resistance, and then use this with the large-resistor RC charge/discharge test to figure out the capacitance. That is at least if the series resistance is negligible in comparison to your load resistance, which it might not be if your load is small enough.

Technically, if leakage resistance is just due to constant resistivity of the dielectric, each dielectric material would give the same time constant regardless of the capacitance of its capacitor or the voltage, and this can be calculated solely from the dielectric's permittivity and resistivity. This, along with a known capacitance, can give you the leakage resistance of a capacitor, theoretically speaking of course. Inversely, you'd be able to calculate capacitance just from the known time constant and measured series DC current. Too bad getting concrete values for resistivity and dielectric permittivity is nigh on impossible, so if you wanted to make a capacitance meter this way you'd need a lot of measurements on different cap types to figure it out. Have my spreadsheet.

>>1172438
> less than $5
Have you tried Aliexpress lately? Clamp meters for $6.50, trash DMMs like that for $2.70, and an analogue multimeter for $2.40. While I don't think the 9V can burn your house down easily, but no way in kekistan am I ever sticking those into a wall outlet.