An optoisolator, also known as an optical isolator or optocoupler, is an electronic component that transfers electrical signals between two isolated circuits using light. Its primary purpose is to provide electrical isolation, which helps protect sensitive components from voltage spikes, noise, and interference, as well as to create a safety barrier between different voltage levels or ground potentials.

An optoisolator typically consists of an LED (light-emitting diode) and a photodetector, such as a photodiode, phototransistor, or a photo-triac, housed within the same package. When an electrical signal is applied to the input side of the optoisolator, the LED emits light, which is then detected by the photodetector on the output side. The photodetector converts the light back into an electrical signal, which is then used to control the output circuit. Since the input and output circuits are not electrically connected, they remain isolated from each other, preventing the transfer of electrical disturbances or faults. Since this type of optoisolator can only be “ON” or “OFF” they are only capable of transmitting digital signals.

This four channel opto-isolator is ideal for switching high-voltage or high-current loads using low-voltage control signals, such as those from microcontrollers or single board computers. The output is rated to 35V and 50mA – perfect for a small relay or inductive load.