A period-based measurement for grounding capacitance meter with arduino using a relaxation oscillator

Abstract

Abstract This paper focus on the development of a simple and low-cost capacitance measurement for Arduino microcontroller. The working principle of the circuit is based on the period changes of the square-wave signal, which is generated by relaxation oscillator, causes by RC values in the circuit. The relaxation oscillator is based on two different types of op-amp, rail-to-rail and comparator. The output frequency of the oscillator is about 2 kHz to 100 kHz. The range of test capacitors is approximately from 1 pF to 33 pF. The percent error of each type of op-amp due to nonlinearity and parasitic capacitance is presented. Finally, the comparison of the experimental results and theoretical analysis as well as precision LCR meter are investigated and discussed.