Development of a MEMS DC electric current sensor applicable to two-wire electrical appliance cord

A non-drive, non-contact MEMS DC electric current sensor to satisfy the increasing needs of DC power supply for monitoring the electricity consumption by either one-wire or two-wire appliance cord has been newly proposed. A micro magnet is integrated into the MEMS-scale DC sensor and the appropriate position for locating the micro magnet has been theoretically pinpointed. A macro-scale prototype DC sensor was therefore fabricated, and an impulse piezoelectric voltage output could be clearly detected out when a DC electric current was applied to a two-wire electrical appliance cord. A linear relationship between the detected peak value of the impulse output voltage and the applied DC electric current was further obtained based on the preliminary measurements.