A Highly Sensitive Electromechanical Small Current Ammeter

We present a novel approach for highly sensitive and resolution-enhanced detection and monitoring of minute current variations using a single clamped-clamped microbeam resonator. The resonator’s stiffness perturbations induced by the input current variation result in a frequency shift. The proposed resonant electric sensor operates close to the buckling region, revealing drastic changes in the deflection profile, which can be exploited for sensitive and high-resolution ammeter applications. We establish and verify the detailed sensitivity enhancement induced by the buckling effects with experimental results. The proposed resonant electric sensor exhibits an enhanced sensitivity of 85Hz/μA, requires a small area, and has a compact structure suitable for portable electronics.