This post explains for the Optocoupler.
The Part Number is MOC7811, M0C7811.
The function of this semiconductor is Optocoupler / Couplers, Interrupters.
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MOC7811 is Optocoupler. An optocoupler, also known as an optoisolator or photocoupler, is an electronic device that combines an optical transmitter (typically an LED) and an optical receiver (usually a phototransistor or photodiode) in a single package. It is designed to provide electrical isolation between input and output circuits.
The optocoupler functions by using light to transmit signals between the input and output sides of the device while maintaining electrical isolation. When an input signal is applied to the LED, it emits light. The light is then detected by the phototransistor or photodiode on the output side, which generates a corresponding electrical signal.
Slotted couplers consist of an infrared emitting diode facing a photodetector in a molded plastic housing. A slot in the housing between the emitter and the detector provides a means of interrupting the signal. A wide selection of standard and custom housings and detector fuctions is available.
1. Signal isolation in digital and analog circuits.
2. Feedback control systems.
3. Switching power supplies.
4. Motor control and drive circuits.
5. Communication interfaces and protocols.
6. AC line voltage monitoring and protection circuits.
Other data sheets are available within the file: MOC7812, MOC7813 MOC7821, MOC7822, MOC7823