A basic resistive pressure sensor, also known as a resistive pressure transducer or pressure-sensitive resistor, is a type of sensor that measures pressure and converts it into an electrical resistance value. These sensors are commonly used in various applications to detect and monitor pressure changes in gases or liquids. Here's how a basic resistive pressure sensor functions:
Sensing Element: The pressure sensor consists of a sensing element made of a resistive material. This material exhibits changes in electrical resistance when subjected to pressure variations. The sensing element may be a thin film, strain gauge, or other resistive material that deforms under pressure.
Electrical Resistance and Pressure Relationship: When pressure is applied to the sensing element, it undergoes mechanical deformation, causing a change in its resistance. The relationship between the applied pressure and the resulting change in resistance is typically calibrated and known beforehand.
Wheatstone Bridge Circuit: The resistive pressure sensor is often incorporated into a Wheatstone bridge circuit. This circuit consists of four resistive arms, with the resistive pressure sensor forming one of the arms. The other three arms may contain fixed resistors with known values. The output voltage of the Wheatstone bridge is proportional to the change in resistance caused by the applied pressure.
Output Signal: As the pressure changes, the resistance of the sensing element also changes, causing an unbalance in the Wheatstone bridge circuit. This unbalance results in a voltage output that is proportional to the pressure applied. The output voltage can then be converted into meaningful pressure units using appropriate signal conditioning and calibration techniques.
Signal Processing: The electrical output from the resistive pressure sensor may require signal conditioning and amplification to improve its accuracy and reliability. Signal processing may involve filtering, amplification, and analog-to-digital conversion to obtain a usable digital signal that can be further processed or displayed.
Pressure Measurement: The final output of the resistive pressure sensor is typically in the form of an analog voltage or a digital signal representing the pressure value. This pressure reading can be used for various purposes, such as monitoring, control, or feedback in a wide range of applications, including industrial automation, automotive, medical devices, and consumer electronics.
Overall, the basic resistive pressure sensor operates on the principle of converting the pressure-induced mechanical deformation of a resistive material into an electrical signal, making it a valuable tool for pressure measurement and control in numerous engineering and industrial applications.