If I have the right understanding of this meter, you should zero the meter with no cap, measure the precision cap and trim the resistance to get the right reading.Mr. Black,
I assembled the capacitance meter kit from Alex and technically it works fine. A few issues though:
I did trim resistance (P1) to 10.0001k ohm (using a high resolution HP multi meter) and assumed I have a perfectly calibrated capacitance meter. First I zeroed the meter and then
I used two precision 1,000 pF 1% caps (provided by Alex) and they measured 1037pF and 1038 pF. What is wrong, the caps or the meter. The caps shouldn't be more than 1010 pF (1%). If the meter needs calibration, do I trim P1? But that gets off the 10k ideal. Or do I use another method?
When measuring Large Caps I've noticed that the meter starts with a value and after that slowly creeps lower, forever it seems. What's the problem, Should I wait until it has stabilized? I stopped waiting after 10 minutes.
In that case why bother with a 7 digit display.1.5% accuracy on a low cost bit of kit like this is not bad really