Differential charge amplifier for piezoelectric sensor

摘要

The amplifier involves a piezoelectric sensor which has a common mode voltage (E) superimposed on two measurement signals. The sensor (10) has two channels each comprising a source of alternating voltage connected in series with capacitors of equal value and produces output currents (I1,I2). The piezoelectric sensor output currents are supplied to an inverter (21) which consists of an operational amplifier (22) having two equal feedback resistors (23,24). The output from the inverter (I1-I2) is supplied to an integrator (25) comprising an operational amplifier (26) with capacitor (27) feedback which produces a signal (VS) proportional to the required acceleration.