Study on the Measurement of Micro-capacitance Based on RLC Series Resonance and Increment

Micro-capacitance can’t be measured precisely with ordinary capacitance-meter because the meter’s measuring range is always high. Even if some capacitance-meters have a low range grade, it is difficult to measure the capacitance value accurately due to the parasitic capacitance in the circuit and the meter. A method of micro-capacitance’s measurement is put forward in this paper. This kind of method is based on principles of RLC series resonance and increment ingeniously. The lower capacitance, the higher quality factor is, so the more accurate resonant frequency can be measured, and the more accurate capacitance value can be received. Meanwhile, the value of parasitic capacitance can be eliminated smartly by means of increment. In this way, micro-capacitance can be measured accurately and easily.