A basic resistive pressure sensor, also known as a piezoresistive pressure sensor, is a type of transducer that is used to measure the pressure of a fluid or gas. It works on the principle of piezoresistivity, which means that the electrical resistance of certain materials changes when subjected to mechanical stress or pressure.
The primary function of a basic resistive pressure sensor is to convert the applied pressure into an electrical signal, which can then be measured and interpreted by electronic circuits. Here's how it typically works:
Structure: The sensor consists of a thin diaphragm or membrane made of a piezoresistive material, often silicon, which is mounted on a rigid backing. When pressure is applied to the diaphragm, it deforms slightly due to the mechanical stress.
Piezoresistive Material: The piezoresistive material used in the sensor has a property that its electrical resistance changes when it undergoes mechanical deformation. The resistance of the material increases or decreases in proportion to the applied pressure.
Wheatstone Bridge Circuit: The piezoresistive material is configured in a Wheatstone bridge circuit. The bridge circuit contains multiple resistors, including the piezoresistive element. When pressure is applied, the resistance of the piezoresistive element changes, causing an imbalance in the Wheatstone bridge.
Output Signal: The unbalanced Wheatstone bridge generates a voltage output proportional to the applied pressure. The output signal is typically very small and may require amplification before it can be used in further electronic processing.
Calibration: To ensure accurate pressure measurements, the sensor may require calibration to establish a linear relationship between the applied pressure and the output voltage.
Signal Processing: The amplified signal can be further processed by electronic circuits or microcontrollers to provide a digital readout or transmit the pressure data to other devices or systems.
Basic resistive pressure sensors are widely used in various applications, including automotive systems (e.g., tire pressure monitoring), industrial process control, medical devices, consumer electronics (e.g., smartphones), and weather monitoring, among others, where precise pressure measurements are required.