Principle and application of strain gauge pressure sensor
A strain gage is a sensitive device that converts strain changes on a device under test into an electrical signal. It is one of the main components of a piezoresistive strain sensor. The most widely used resistance strain gauges are metal resistance strain gauges and semiconductor strain gauges. The metal resistance strain gauge has two kinds of filament strain gauges and metal foil strain gauges. Usually, the strain gauge is tightly bonded to the mechanical strain matrix by a special adhesive. When the stress changes due to the force of the substrate, the strain gauges are also deformed together, so that the resistance of the strain gauge is changed, thereby The voltage applied to the resistor changes. Such strain gauges typically have a small change in resistance when subjected to force. Typically, such strain gauges are formed into strain bridges and amplified by subsequent instrumentation amplifiers and then transmitted to the processing circuitry (usually A/D conversion). And CPU) display or actuator.
It consists of a base material, a metal strained wire or a strained foil, an insulating protective sheet, and a lead wire. Depending on the application, the resistance of the strain gauge can be designed by the designer, but the range of resistance should be noted: the resistance is too small, the required drive current is too large, and the heat of the strain gauge causes the temperature to be too high. Used in different environments, the resistance value of the strain gauge is changed too much, the output zero drift is obvious, and the zero adjustment circuit is too complicated. The resistance is too large, the impedance is too high, and the ability to resist external electromagnetic interference is poor. Generally, it is about tens of euros to several tens of kiloohms.
