Meaning
Solid-state sensing instruments that measure mechanical strain through changes in electrical resistance utilize semiconductor materials bonded to a flexible substrate. In a piezoresistive pressure transducer, the strain gauges are integrated directly into a silicon diaphragm to detect minute pressure variations. This design provides high sensitivity and rapid response times, making it suitable for dynamic flow measurements.
The sensor is widely used in automotive manifolds and aerospace test benches to monitor critical fluids.
Diaphragm Deflection
Physical pressure applied to the silicon sensor deforms the internal structure and alters resistivity. Inside a piezoresistive pressure transducer, this deformation is measured using a Wheatstone bridge circuit. The bridge converts the change into a proportional differential voltage.
Temperature Compensation
Semiconductor materials exhibit high sensitivity to thermal variations, which can cause measurement drift if left uncorrected. A piezoresistive pressure transducer must incorporate a thermistor or an onboard compensation network to adjust the output signal for ambient temperature changes. This correction is performed either by analog trimming resistors or by digital calibration tables in the sensor electronics.
Signal Amplification
Raw electrical output from the sensing bridge is in the millivolt range and requires boosting before transmission. In a piezoresistive pressure transducer, an onboard instrumentation amplifier increases the signal level to a standard zero-to-five volt or four-to-twenty milliamp output. This high-level signal resisting noise is easily transmitted over longer distances.
