Semiconductor-based electret sensors for sound and pressure

The theory and experimental results for integrated electret-based silicon sensors for the detection of sound and pressure are presented. A silicon electret microphone for use in hearing-aids is described. It has an experimentally determined sensitivity of 19 mV/Pa in the frequency range of 50 Hz to 10 kHz. The realization of a pressure sensor for application in catheter-tip blood-pressure measurements is discussed. This type of electret sensor appeared to have a pressure sensitivity of 1.6 mu V/Pa in the required frequency range of 0 to 100 Hz.<
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