There are many types of mechanical sensors, such as resistance strain gauge pressure sensors, semiconductor strain gauge pressure sensors, piezoresistive pressure sensors, inductive pressure sensors, capacitive pressure sensors, resonant pressure sensors, and capacitive acceleration sensors. But the most widely used is the piezoresistive pressure sensor, which has a very low price and high accuracy and good linearity. Below we mainly introduce such sensors.
In understanding the piezoresistive force sensor, we first understand the element such as a resistance strain gauge. The resistance strain gauge is a sensitive device that converts the strain change on the DUT into an electrical signal. It is one of the main components of a piezoresistive strain sensor. The most commonly used resistance strain gages are metal resistance strain gages and semiconductor strain gages. There are two types of metal resistance strain gauges: wire strain gauges and metal foil strain gauges. Usually, the strain gauge is tightly adhered to the substrate that generates mechanical strain through a special adhesive. When the substrate undergoes a stress change, the resistance strain gauge also deforms together, so that the resistance value of the strain gauge changes, thereby The voltage applied to the resistor changes. Such strain gauges usually have a small change in resistance when they are stressed. Generally, these strain gauges form a strain bridge, which is amplified by a subsequent instrumentation amplifier and then transmitted to the processing circuit (usually A / D conversion). And CPU) display or actuator.
