What is Opto-coupler?
Ø Opto-coupler is an electronic component that transfers electrical signals from one circuit to another circuit with isolation Ø These are also known as Opto-isolator, photo coupler, and optical isolator Uses Ø Isolation between circuits Ø It prevents damage in one circuit due to damage in another circuit Ø Prevention of unwanted noise Ø Both circuits can work on different voltage levels Opto-coupler: PC 817 Ø It has four pins Ø Pin-1 is Anode & 2 is Cathode of the LED Ø Pin-3 is Emitter & 4 is Collector of the Photo Transistor Ø When light of LED falls on the Phototransistor base it conducts Ø If there is fault in either circuit, another circuit will remain safe Ø This is 4 pins opto-coupler component Ø Pin-1 is Anode & 2 is Cathode of the LED Ø Pin-3 is Emitter & 4 is Collector of the Photo Transistor Ø Mark on top-left, shows that pin counting starts from here Ø SMD version is also availabl