high-speed sub-femto-farad capacitance measuring system

A high-speed small capacitance measuring system has been designed and implemented on a PCB with discrete electronic components the implemented system was calibrated and tested using one hundred 1 pF capacitors with tolerance of 1% the system sensitivity is 2mVfF for capacitance values in range of 0-2 pF the sensitivity can be increased to 4mV/fF FOR the same capacitance range if the power supply voltage is increased from 5 to 10volts the capacitance measuring time is 1mm and the noise voltage at the output of the system is below 1 mVrms.

Keywords:

small capacitance measurement , electrical capacitance tomography , switched-capacitor amplifier