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.