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What is the function of opto coupler in the switching operation of digital input signal?
When used correctly, an Optocoupler can effectively: Remove electrical noise from signals. Isolate low-voltage devices from high-voltage circuits. Allow you to use small digital signals to control larger AC voltages.
What is an opto coupler IC?
An optocoupler IC, also known as an opto-isolator or photocoupler, is a semiconductor device which is used to couple isolated circuits. Within an optocoupler you will find a light emitter and a light sensor. Optocouplers are often used in high-voltage applications to block the high voltages and variations in voltage.
What kind of transistor is used in opto-coupler?
Opto-coupler which use Photo SCR. In the upper image the internal construction is shown inside a Photo-transistor Optocoupler. The Transistor type can be anything whether PNP or NPN. Photo-Transistor can be further of two types depending on the output pin availability.
Which is the anode pin in the optocoupler?
Pin 1 is an anode pin of IR input within the Optocoupler. It will give the logical input signal to the internal IR. Pin 2 is the cathode pin of the IR within the optocoupler. It will give the IR to make the common ground with the circuit and Power supply.
What is the internal structure of the opto coupler?
This the internal structure of the opto-coupler. On the left side pin 1 and pin 2 are exposed, it is a LED (Light Emitting Diode), the LED emit infrared light to the photosensitive transistor on the right side. The photo-transistor switches the output circuitry by its collector and emitter, same as typical BJT transistors.
How is optocoupler used in DC based switching?
In the upper image the internal construction or the TRIAC based opto-coupler is shown. TRIAC is mainly used where AC based control or switching is needed. The led can be controlled using DC, and the TRIAC used to control AC. Opto-coupler provide excellent isolation in this case too.