Six kinds of novice must understand the application of optical coupler

What is an optocoupler? The photoelectric coupling device (referred to as an optocoupler) is a conversion device that combines a light-emitting device (such as a light-emitting diode) and a photosensitive device (such as a phototransistor), and realizes coupling by electric light to form an electric light and a light-electrical. Optocouplers are subdivided into various types, as shown in one of their internal structure diagrams, namely the 6-pin package triode acceptor type. The main applications are as follows.

(1) Application on logic circuits

The optocoupler can form numerous logic circuits. Since anti-interference performance and isolation performance of the optocoupler are better than those of the transistor, the logic circuit formed it is more reliable.

(2) as a solid state switch application

In the switching circuit, it is often required to have good electrical isolation between the control circuit and the switch, which are difficult for a typical electronic switch. But it is not difficult to implement with a photocoupler.

(3) Application on the trigger circuit

The optocoupler is used for the bistable output circuit. Since the LEDs can be respectively connected into the two-tube emitter circuits, the problem of isolation between the output and the load can be effectively solved.

(4) Application in pulse amplifier circuit

Applying to a digital circuit, the pulse signal can be amplified.

(5) Application on line circuits

Linear optocouplers are used in linear circuits with high linearity and excellent electrical isolation.

(6) Application for special occasions

Optocouplers can be used in high voltage control, replacing transformers, replacing contact relays, and for A/D circuits.

In addition, it should be noted that an independent power supply must be used only for the input and output sections of the optocoupler. If one power supply is shared at both ends, the isolation is not.

Moreover, when optocouplers are used to isolate the input and output channels, all signals (including numerical multiples, control signals, and status signals) must be isolated so that there is no electrical connection between the isolated sites. Isolation is also meaningless.