I am using AD5933 evaluation board and assessing its accuracy for impedance measurement in frequecy range of 10kHz-200kHz. I have following queries:
1. What value of excitation voltage be chosen for measuring impedance of capacitor of order of pico Farads?
2. In which all cases should we use one of the four different combinations of calibration impedance? Is it necessary that to measure impedance of a capacitance, calibration is done through capacitor only?
3. I am attaching my findings of impedance for different capacitors at two different frequencies. The error is very large in my case.
I would be grateful if someone may help.