– utilizing silicon as a measuring material and diaphragm, the circuit can be integrated
– more sensitive than metal because strain (displacement) and piezoresistive properties appear together
– always use 4 gauge in bridge, problem faced
- gauge is not identical
- very sensitive to temperature
– alternative solutions:
- excitation current
- bridge voltage compensation
- amplifier amplification compensation
Figure 3.53 Straingage piezoresistif:
(a) phizic peizoresistive straingage,
(b) the characteristics of peizoresistive sg,
(c) temperature response at the bridge configuration
– construction of silicone pressure sensors
- diaphragm with etching process
- strain gauge with dopant diffusion
Figure 3.54 Pressure type sensor of silicon diaphragm: (a) flat diaphragm, (b) circular diaphragm more sensitive
– construction of a silicone pressure sensor package with a series of compensation and amplifier
Figure 3.55 Semiconductor pressure sensor:
(a) the sensor construction, (b) the block diagram of the sensor circuit