What is a sensor? Broadly speaking, a sensor (transducer/sensor) is a device that can convert a physical quantity or a chemical quantity into a convenient electrical signal.

The definition of the International Electrotechnical Commission (IEC: International Electrotechnical Committee) is as follows: "Sensor is a front-end component in a measurement system, which converts input variables into signals that can be measured."

The national standard GB7665-87 defines the sensor as: "A device or device that can feel the specified measured and converted into a usable signal according to a certain law (mathematical function rule), usually composed of sensitive elements and conversion elements."

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At present, the progress made in information processing technology and the rapid development of microprocessor and computer technology require corresponding progress in the development of sensors. Microprocessors are now widely used in measurement and control systems. With the enhancement of the capabilities of these systems, as the front-end unit of the information collection system, the role of sensors becomes more and more important. The sensor has become a key component in the automation system and robot technology. As a structural component in the system, it is the first gate for the input of the measured signal.

Sensor main classification

1. It can be divided into pressure-sensitive and force-sensitive sensors, position sensors, liquid level sensors, energy consumption sensors, speed sensors, acceleration sensors, ray radiation sensors and thermal sensors.
2. According to the principle, it can be divided into: vibration sensor, humidity sensor, magnetic sensor, gas sensor, vacuum sensor, biological sensor, etc.
3. According to the output signal, it can be divided into: analog sensor, digital sensor, digital sensor, switch sensor.

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The role of the sensor

A sensor is actually a functional block, a physical device or biological organ that can detect and feel external signals, physical conditions (such as light, heat, humidity) or chemical composition (such as smoke), and pass the detected information to Other devices or organs. "Sensor" is defined in the Xinwei Dictionary as "a device that receives power from one system and usually sends power to the second system in another form."　　According to this definition, the role of the sensor is to convert one energy into another energy form, so many scholars also use "Transducer" to call "Sensor", its role is to convert various signals from the outside into electrical signals.
The sensor is also called the electric facial features, which is the extension of the human facial features. The function of the sensor is comparable to the five major human sensory organs:
Photosensitive sensor-vision
Acoustic sensor-hearing
Gas sensor-smell
Chemical sensor-taste
Fluid sensor-tactile