Many times actuators (motors, relays, secondary control circuits, or other miscellaneous loads) require a separate power source than that of the controlling elements.(microcontroller, computer, or primary control circuit) In order to isolate separate power sources or keep output circuits from affecting the input circuits a device called an optical coupler can be used.
Optical Coupling Devices
Many times actuators (motors, relays, secondary control circuits, or other miscellaneous loads) require a separate power source than that of the controlling elements.(microcontroller, computer, or primary control circuit) In order to isolate separate power sources or keep output circuits from affecting the input circuits a device called an optical coupler can be used.
The input side of these devices is nothing more than an LED and requires a current limiting resistor. The output side can be a simple photodiode, bipolar junction phototransistor, photodarlington transistor pair , photoscr, photodiac, or a phototriac.
