I am trying to build a capacitance meter using a simple relaxation oscillator with a fixed resistor R in series with a capacitor to be measured C. I am applying the formula where Freq=frequency and K is a constant.:
C = K / ( R * Freq )
I have however noticed parasitic capacitance in the circuit that affects the measured capacitance and frequency. I am therefore looking for a correct formula that takes into consideration of 2 extra parasitic phantom capacitors, C1 which is in parallel with R and C2 which is in parallel with C. The resulting formula should be in the form of:
C = f( R, C1, C2, K, Freq)
Looking forward to any assistance with this problem.