Capacitance Meter

A capacitance meter has been constructed, based on a PIC microcontroller development board and OLED display.  A Capacitive Voltage Divider, CVD, comprising the capacitor under test, Cut, and sample/hold capacitor, Chold, of the integrated PIC ADC was used to derive the capacitance of Cut,  by the 'double sample', differential CVD measurement method.

VCHOLD1 = sample 1 voltage across the internal ADC hold capacitor.

VCHOLD2 = sample 2 voltage across the internal ADC hold capacitor.

CUT = capacitance in picoFarads of the capacitor under test.

After designing a suitable jig, the meter will be useful in determining the value of unmarked smd capacitors.

Cut is two 22pF capacitors in parallel

ADC = Analogue to Digital Converter.