MEMS-based voltage detector

• We use the microelectromechanical force to detect small low-frequency voltages.
• We show that noise contribution of readout electronics vanishes at pull-in.
• We verify the measurement principle experimentally with a MEMS accelerometer.
• With an optimized MEMS component, the method can compete with electrical devices.

A novel principle of low-noise voltage measurement based on microelectromechanical systems (MEMS) is introduced and experimentally demonstrated. The method is based on parametric conversion of voltage via electromechanical force to the amplitude of the RF signal of the capacitive measurement circuit that detects the displacement of a moving-plate MEMS capacitor. Both theory and experiments show that the noise of voltage measurement can be considerably decreased by biasing the MEMS device near its pull-in point. Experimental results are in agreement with theoretical predictions and they indicate the potential of the method as a competitor of state-of-the-art low-noise voltmeters in special applications.