An RC Discharge Digital Capacitance Meter

A simple digital capacitance meter which utilizes the RC discharge is proposed and the wide range capability from 0.1 pF to 10 mF and the excellent linearity to ± (0.02 percent of reading + 1 digit) are shown. The RC discharge capacitance meter provides the capacitance to be measured at a frequency which is reciprocal to the product of the discharge resistance and the measured capacitance. Therefore, the meter can be used to test the frequency dependence of the capacitor even though the test signal is a dc voltage. The proposed RC Discharge Capacitance Meter can also be used in applications such as the measurement of the deviation from the preset value, or the torellance check of capacitance to make the GO or NO-GO decision by adding a few logic gates.