Embedded Lab

Optoisolators, also known as optocouplers or photocouplers, are a very useful component in transferring electrical signals between two circuit blocks, while providing a complete electrical isolation between the two blocks. The key advantage of using an optoisolator is it blocks high voltages and voltage transients in one block being transferred to other, so that a surge in one part of the system will not disrupt or destroy the other parts. An opto-isolator connects the two blocks with a beam of light, which is modulated by input current. In this tutorial, Dan explains the basics of optoisolators and illustrates its working principle by making one using a light-emitting diode and a light-dependent resistor.