A basic resistive pressure sensor is a type of transducer that converts the applied pressure into a change in electrical resistance. It operates on the principle that the resistance of a material changes when it is subjected to mechanical deformation. The basic structure of a resistive pressure sensor typically involves a flexible diaphragm or membrane that deforms in response to changes in pressure. This diaphragm is often made of a material that exhibits a change in resistance when stretched or compressed.
Here's how the basic operation of a resistive pressure sensor works:
Diaphragm Deformation: When pressure is applied to the sensor, the flexible diaphragm or membrane undergoes mechanical deformation. The diaphragm might either stretch or compress, depending on the design of the sensor.
Resistance Change: The material used in the diaphragm has a characteristic known as the piezoresistive effect, where its electrical resistance changes in response to mechanical strain. When the diaphragm deforms due to pressure, the resistance of the piezoresistive material changes.
Electrical Circuit: The resistive pressure sensor is incorporated into an electrical circuit. It forms one of the elements in a resistive bridge circuit or a Wheatstone bridge. This circuit typically includes a voltage source and other resistors.
Output Voltage: As the resistance of the piezoresistive material changes due to pressure-induced deformation, the balance of the Wheatstone bridge circuit is disturbed. This imbalance results in an output voltage that can be measured and correlated to the applied pressure.
Pressure Measurement: By measuring the output voltage of the circuit, which changes in proportion to the applied pressure, the pressure value can be determined. Calibration and mathematical techniques are used to relate the output voltage to the actual pressure value.
Resistive pressure sensors are relatively simple in design and can be used for measuring a wide range of pressures in various applications, including automotive systems, industrial automation, medical devices, and consumer electronics. However, they might have limitations in terms of accuracy, sensitivity, and temperature stability compared to more advanced pressure sensing technologies like capacitive, piezoelectric, or MEMS-based sensors.