A basic resistive pressure sensor, also known as a resistive pressure transducer or strain gauge pressure sensor, is a type of sensor used to measure pressure in various applications. Its primary function is to convert the applied pressure into an electrical signal that can be easily measured and processed by electronic circuits. Here's how it typically works:
Mechanical Sensing Element: The sensor consists of a mechanical sensing element that deforms when subjected to pressure. The mechanical element is usually a diaphragm or a thin membrane that flexes or changes shape as the pressure is applied to it.
Strain Gauge: Attached to the mechanical element is a strain gauge. A strain gauge is a small resistor made from a special material that changes its resistance when subjected to mechanical strain or deformation. As the diaphragm flexes due to pressure, the strain gauge experiences a corresponding change in resistance.
Wheatstone Bridge Configuration: The strain gauge is often connected in a Wheatstone bridge configuration. A Wheatstone bridge is a circuit arrangement that measures small changes in resistance with high sensitivity. When pressure is applied, the resistance of the strain gauge changes, unbalancing the Wheatstone bridge.
Output Signal: The unbalanced Wheatstone bridge generates a voltage output proportional to the pressure-induced strain on the mechanical element. This output voltage is typically very small and may require amplification for accurate measurement. The output is linearly related to the applied pressure, assuming the strain-stress relationship of the sensing element is within its elastic limits.
Signal Processing: The output voltage from the Wheatstone bridge is then processed by electronic circuits, such as signal conditioning and amplification, to provide a usable and measurable output. Depending on the application, additional signal processing might be used to calibrate, linearize, or compensate for temperature effects or other variables.
Readout or Display: The final processed output can be displayed on a digital screen, recorded, or used for control purposes in various applications, such as automotive systems, industrial processes, medical devices, aviation, and many others.
In summary, the basic resistive pressure sensor converts applied pressure into a change in resistance through a strain gauge, which, in turn, is used to generate an electrical output proportional to the pressure, allowing for easy measurement and integration into electronic systems.