Optocoupler component analysis

What is an optocoupler? What does it do? Optocoupler (opticalcoupler equipment, English abbreviation OCEP) is also called an optoelectronic isolator or optocoupler, referred to as an optocoupler. It is a device that uses light as a medium to transmit electrical signals. Usually, the emitter (infrared light-emitting diode LED) and the light receiver (photosensitive semiconductor tube, photoresistor) are packaged in the same tube. When a power signal is applied to the input end, the light emitter emits light, and after receiving the light, the photoreceiver generates photocurrent, which flows out from the output end, thereby realizing "electricity-optical-electricity" conversion. The optocoupler uses light as the medium to couple the input signal to the output. Because it has the advantages of small size, long life, no contacts, strong anti-interference ability, insulation between output and input, and one-way signal transmission, it is widely used in digital applications. It is widely used in circuits.

There are two types of optocouplers: one is nonlinear optocoupler, and the other is linear optocoupler.

Commonly used 4N series, such as 4N25, 4N35, 4N26, 4N36, etc. Optocouplers are nonlinear, and commonly used linear optocouplers are PC817A--C series, PC111, TPL521-1, etc.

There are many types of commonly used optocouplers, but there are only 4 types commonly used in home appliance circuits:

1. The first category is a photocoupler packaged with a light-emitting diode and a phototransistor. The structure is a dual in-line 4-pin plastic package. The internal circuit is shown in Table 1. It is mainly used in switching power supply circuits.

2. The second category is a photocoupler packaged with a light-emitting diode and a phototransistor. The main difference is the pin structure. The structure is a dual in-line 6-pin plastic package. The internal circuit is shown in Table 1. It is also used in switching power supply circuits.

3. The third category is a photocoupler packaged with a light-emitting diode and a phototransistor (with a base terminal). The structure is a dual in-line 6-pin plastic package. The internal circuit is shown in Table 1. It is mainly used in AV conversion audio circuits.

4. The fourth category is a photocoupler packaged with a light-emitting diode and a photodiode plus a transistor (with a base terminal). The structure is a dual in-line 6-pin plastic package. The internal circuit is shown in Table 1. It is mainly used in AV conversion video circuits. middle.

Category 1: PC817 PC818 PC810 PC812 PC502 LTV817 TLP521-1 TLP621-1 ON3111 OC617 PS2401-1 GIC5102

Category 2: TLP632 TLP532 TLP519 TLP509 PC504 PC614 PC714 PS208B PS2009B PS2018 PS2019

Category 3: TLP503 TLP508 TLP531 PC613 4N25 4N26 4N27 4N28 4N35 4N36 4N37

Category 4: TLP551 TLP651 TLP751 PC618 PS2006B 6N135 6N136

2. Substitution principle

All of these categories are interchangeable. Category 1 and Category 2 are interchangeable, but the pins must be aligned. Category 3 can replace Category 1 and Category 2, but Category 1 and Category 2 cannot replace Category 3. The above is the knowledge analysis of optocoupler, I hope it can help you.