Damping of compression and shear piezoelectric accelerometers by electro-mechanical feedback

Piezoelectric (PE) accelerometers exhibit a very pronounced resonance peak in their transfer characteristic of typically 30 dB or more. By a simple modification of existing accelerometers, providing them with an electrical-sensor output as well as an electrical-actuator input and using a charge amplifier in a feedback-path between the sensor output and the actuator input, this pronounced resonance peak can be suppressed almost entirely, thereby extending the transducer´s useful frequency range considerably. Because a PE accelerometer is normally read out by a charge amplifier, no extra circuitry (expense) is necessary to provide this electromechanical feedback. To avoid the extra connector (for the actuator input), the charge amplifier should be integrated into the transducer´s mounting base. The necessary power can then be provided via the connector cable, whereby the acceleration can be obtained externally from the current modulation of the constant-voltage power supply. This allows low-resistance readout of accelerometers (no sensitivity to parasitic cable impedances) and utilizes the full potential bandwidth of these PE inertial accelerometers