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.
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| Cut is two 22pF capacitors in parallel |
ADC = Analogue to Digital Converter.
