Photoelectric sensor is a kind of optical principle to detect the presence of objects、position、Speed and other parameters of the sensor。According to different classification criteria，Photoelectric sensors can be divided into many types。The following is a detailed introduction to the classification of photoelectric sensors：

one、Classification by working principle

1. Photoelectric switch：It is mainly used for object detection and position judgment，It is widely used in uninterrupted assembly line production on automated production lines。It detects the presence or change of position of objects by blocking or reflecting light，And output the corresponding electrical signal。

2. Photoelectric encoder：Applications based on displacement measurement，Widely used in machine tools、measure、Communication and other fields。It uses the principle of photoelectric conversion，Convert mechanical displacement into electrical output，Used to measure and control the position of objects、Velocity isoparameter。

3. Other types of photoelectric sensors：These sensors rely on an objects reflection of light、Transmission or absorption to realize the monitoring and measurement of object parameters，Mainly used for color、luminance、Light intensity、Distance and other detection aspects。Such as，Reflective photosensors work by detecting the light reflected off an objects surface；The scattering photoelectric sensor works by detecting the amount of light reflected back by the object being measured；Infrared photoelectric sensors use infrared light to detect objects，It is often used to detect small moving or hidden objects。

two、Classification by photoelectric element

1. photoresistor：A widely used photosensitive electronic device，Can be used for light intensity detection。It has a simple structure、Low price、The dynamic response speed is fast。

2. photodiode：Widely used，Including photoelectric isolation、Photoelectric switch、Various photoelectric meters, etc。Photodiodes have high speed response、Advantages of high sensitivity，It is one of the commonly used photoelectric components in photoelectric sensors。

3. photocell：Also known as optocoupler，It consists of a photosensitive battery and a semiconductor amplifier。It is used to isolate input and output circuits，It plays the role of good stability and strong anti-interference ability。

three、Classification by detection mode

1. Diffuse reflection type photoelectric sensor：A receiver and transmitter in one，When an object passes through the light path，The object being detected reflects a sufficient amount of light emitted by the photoelectric sensor transmitter back to the receiver，The photoelectric switch generates the selective signal。

2. Mirror reflection type photoelectric sensor：Also a receiver and transmitter in one，But it works when an object passes through the detection path，The light emitted by the photoelectric sensor light source transmitter is blocked to reflect back to the receiver，The photoelectric sensor generates the electrical signal for detection。

3. Beam type photoelectric sensor：Structurally separate，It consists of two parts: transmitter and receiver。Under normal conditions, the light from the transmitter can be directly received by the receiver，If theres an object blocking the line of fire，The photoelectric sensor generates an electrical signal。This sensor is mainly used to detect opaque objects and objects with poor light reflection。

4. Channel type photoelectric sensor：Standard is usually usedUFont structure，Its receiver and transmitter are located respectivelyUThe inside of the type groove is opposite，On the same line。When the detected object passes byUProfile groove time，Blocking the receiver to receive the light signal，The photoelectric sensor generates an open sensing signal。

To sum up，The photoelectric sensor can work according to the principle、Various classification methods such as photoelectric components and detection methods are classified。Different types of photoelectric sensors in industrial automation、Robot technology、Safety monitoring and other fields have a wide range of applications。