An optocoupler is a device that isolates a circuit, which enables electronic equipment to perform data transmission and control on the premise of ensuring circuit safety. Today, Freixin will introduce in detail the working principle, application scenarios, classification and advantages and disadvantages of optocouplers.

1. Working principle

1. The optocoupler is composed of a light-emitting diode (LED for short) and a photosensitive diode (PD for short). When a positive voltage is applied to the LED terminal, the LED produces light of the corresponding color. When 0V is applied to the LED terminal, the LED stops working and does not emit light.

2. When the light reaches the PD, the PD generates a reverse current or voltage. In this way, the LED and PD circuits form a one-to-one photoelectric conversion circuit. In this circuit, the PD collects the light from the LED, so that the circuit is isolated, and a high impedance (high barrier) is formed between its output and input.

2. Application scenarios

1. Internet server internal communication

In a large data center, there are a large number of servers, and the communication between servers needs to ensure speed and isolation. The optocoupler can provide such an isolation function, so that the servers will not interfere with each other and ensure the data transmission speed.

2. Industrial control field

Industrial control faces many difficulties, for example, electrical noise may be generated when industrial equipment is running, which will interfere with the control system, resulting in loss of control or even damage to the equipment. The isolation function of the optocoupler can solve this problem and ensure the stability and reliability of the circuit, thereby ensuring the normal operation of the equipment.

3. Household electrical appliances

Optocouplers are also commonly used in home appliances. For electrical appliances such as range hoods, microwave ovens, and induction cookers, their operating controllers need to be isolated on the circuit, otherwise it will bring danger to users. Therefore, the optocoupler can isolate the controller of the electrical product and ensure the safe use of the user.

3. Classification and advantages and disadvantages

1. Classification

According to different functions, optocouplers can be divided into three types: inverting type, common emitter type and bidirectional type. Among them, the inverting optocoupler is often used for digital isolation, the common emitter optocoupler is often used for analog isolation, and the bidirectional optocoupler can perform both analog isolation and digital isolation.

2. Advantages and disadvantages

advantage:

a. With isolation performance, it can avoid the transmission of current and voltage;

b. It has the ability of instantaneous recovery and automatic recovery of faults;

c. It has the characteristics of miniaturization, safety and reliability, and wide application range;

shortcoming:

a. The efficiency is not very high, about 20%~25%;

b. It is easy to lose the perfect isolation performance under high temperature, high frequency or high voltage environment.

In short, the optocoupler is a very important electronic component, which provides us with a very reliable solution in terms of data transmission and circuit control through the technology of photoelectric isolation. In practical applications, we need to select different types of optocouplers according to actual needs to achieve the best results.