Here is the schematic of my capacitor meter I built and have used quite a bit. It will measure from zero to 0.1uf with 300pf at mid range. It is an oscillator that makes noise fed into a bridge circuit that will null out the noise when balanced. Once built, you must clip in known value capacitors and hand calibrate the dial.
I built my unit into a cheap push on battery light the output can go to a small audio amp, audio input of a computer, or try a piezo speaker. The noise is rather annoying, so you may want to use a scope to view it if you must test many capacitors.