| 摘要 |
A piezoelectric and/or electret sensing device (10) comprises a piezoelectric and/or electret transducer (12) for producing a measurement current in response to mechanical stimulus, and a control and evaluation circuit connected to the transducer. The control and evaluation circuit (14, 24, 26, 28, 30) comprises a transimpedance amplifier (14) having a first and a second input, the transducer being operatively connected between the first input and a reference node, and an electrical waveform generator (22) for generating an electrical waveform, the electrical waveform generator being operatively connected between the second input and the reference node. The transimpedance amplifier controls the first input such that the difference in electric potential between the first input and the second input be cancelled and outputs an output voltage indicative of electrical current flowing across the transducer. The control and evaluation circuit identifies a first component of the output voltage indicative of the measurement current and a second component of the output voltage indicative of the current caused by the generation of the waveform and detects a short circuit and/or a broken wire based upon the second component. |
