Common Types Of Sensors

Resistive type
Resistive sensors are devices that convert physical quantities such as displacement, deformation, force, acceleration, humidity, temperature, etc. to resistance values. There are mainly resistive sensors such as strain gauge, piezoresistive, thermal resistor, thermistor, gas sensor, and humidity sensor.
Resistive strain gauge
The resistance strain gauge in the sensor has the strain effect of metal, that is, it produces mechanical deformation under the action of external force, so that the resistance value changes accordingly. Resistance strain gauges are mainly divided into two types: metal and semiconductor. Metal strain gauges are divided into metal wire type, foil type, and film type. Semiconductor strain gauges have the advantages of high sensitivity (usually dozens of times that of wire type and foil type) and small lateral effect.
Piezo-resistive type
The piezoresistive sensor is a device made of diffused resistors on the substrate of semiconductor material based on the piezoresistive effect of semiconductor material. Its substrate can be directly used as a measuring sensor element, and the diffused resistors are connected in the substrate in the form of a bridge. When the substrate is deformed by external force, the resistance values ​​will change, and the bridge will produce corresponding unbalanced output.
The substrate (or diaphragm) materials used for piezoresistive sensors are mainly silicon wafers and germanium wafers. Silicon piezoresistive sensors made of silicon wafers as sensitive materials are increasingly valued by people, especially solid-state piezoresistive sensors for measuring pressure and speed are the most widely used.
Thermal resistors
Thermal resistor temperature measurement is based on the characteristic that the resistance value of metal conductors increases with the increase of temperature to measure temperature. Most thermal resistors are made of pure metal materials, and the most commonly used are platinum and copper. In addition, materials such as nickel, manganese and rhodium have begun to be used to manufacture thermal resistors.
Thermal resistor sensors mainly use the characteristic that the resistance value changes with temperature to measure temperature and temperature-related parameters. This type of sensor is more suitable for occasions where the temperature detection accuracy requirements are relatively high. The more widely used thermal resistor materials are platinum, copper, nickel, etc. They have the characteristics of large resistance temperature coefficient, good linearity, stable performance, wide operating temperature range, and easy processing. It is used to measure temperatures in the range of -200℃ to +500℃.