A sensor is a device that receives a signal or stimulates and reacts, and can convert a physical quantity or a chemical quantity to be measured into another corresponding output device. Used for automation control, security equipment, etc. In the stimulus theory, in order to obtain electrical stimulation, electronic stimulation devices are used during this time.
One type of device that has been used for a long time is one type of induction coil, but it has not been used here, and is mostly replaced by a vacuum tube and a semiconductor stimulation device.
The national standard GB7665-87 defines the sensor as: "A device or device that can be measured and converted into a usable signal according to a certain rule, usually composed of a sensitive component and a conversion component." The sensor is a detecting device that can sense the measured information and can transform the detected information into an electrical signal or other required form of information output according to a certain law to meet the information transmission, processing, storage, Requirements for display, recording and control. It is the first step in achieving automatic detection and automatic control.
"Sensor" is defined in the new Wei-style dictionary as: "Power is received from one system, and power is usually sent to the device in the second system in another form."