Photodiode optoisolator is used in an Opto coupled solid-state relay and it drives a power switch. LEDs can sense light and can also emit it. The sensor which is used could be a photoresistor, photodiode, or a phototransistor. A photosensor and an optical channel can detect the light and can generate the electrical energy directly or it can modulate the electric current which flows from an external power supply. Optoisolator has a source of light, which is almost always a near-infrared light-emitting diode that can convert the electrical input signals into light. The two major important elements needed for an optoisolator is light emitter and a light detector. How does optocoupler or optoisolator work Mostly optical isolators are used to prevent the high voltage or rapidly changing voltages on one side of the circuit from damaging a component or distorting transmission on the other side. Most of the machine controlling equipment generates induced noise that may cause malfunctions with the help of optocouplers we can isolate this noise in the input signals.

Opto-isolators can withstand input to output voltages up-to 10KV and voltages transients with speed up to 10KV. It can prevent high voltages or rapidly changing voltages damaging the components by isolating the overvoltage signals. Opto-isolator is also known as an optical isolator, or optocoupler, it is a device that transfers an electric signal or voltage from one circuit to another by using the light, while it isolates the two circuits from each other.

Opto isolator circuit