which relies on the piezoresistive effect of semiconductors under a mechanical load. Here, as well as depending on the strain, the measured value is also highly dependent on the temperature.
The measuring grid consists of a strip of semiconductor just a few tenths of a mm wide a few hundredths of a mm thick applied to a support, which — like the metal strain gauge — is stuck to the body of the sensor (Figure H 3).
The sensitivity to strain of the semiconductor strain gauge is greater than that of the metal strain gauge by a factor of 25 to 50 — as is the sensitivity to interference, however, which explains why semiconductor strain gauges have failed to establish themselves as well as had been hoped.
Figure H 3: Semiconductor strain gauge