Puretus has been working on a high resolution capacitance meter:
One day I was looking for methods to measure capacitances of cap components. Even though it is pretty trivial now with my new Brymen multimeter, I ran into this design by Roman Black which turned out to be very well explained and in terms of learning this looks an interesting project to build. I was hoping that Roman would have included source code for the PIC16F628.
I’m confused about the “high res” claims. This uses a 1% reference resistor; what is the point of having a six digit display if the bottom three or four are random numbers?
@Jim B: Read the “Real” accuracy section for a bit more detail about the accuracy.
I agree that it’s a bit confusing though. If you really need 7 digits you probably care about precision a bit more than that. Of course, if you want to build one you’re free to choose higher precision components and even add components for calibration.
This too, I need to look into (as well as Doc Brown’s Capacitor ESR meter!)
The lnk is a “404” now.