Magnetically actuated resonant piezoresistive microcantilever operating in fluid for dc current measurement

A novel dc current sensor based on magnetically actuated resonant piezoresistive microcantilever is proposed. The sensor measures the dc current by detecting the shift of resonant frequency of the microcantilever. A detailed theoretical study on the relationship between the current and the cantilever´s resonant frequency is also given. To reduce force and displacement noise, the microcantilever works in the fluid with good thermal conductivity. The experimental results show that the sensor can achieve a sub-milliampere resolution and the accuracy is found to be 3.93% for the current range of 0.5 to 5 mA.