Hello friends, I hope you all are doing great. Today, I am going to share the new PC817 Optocoupler Library for Proteus . An optocoupler joins two circuits with nothing but light: an infrared LED on one side, a phototransistor on the other, and a clear gap between them that can hold off thousands of volts. It is how a 3.3 V or 5 V microcontroller reads a 24 V machine signal, how it switches a load on another supply without sharing its ground, and how a mains power supply tells its controller what the output is doing. Updates PC817 Optocoupler Library for Proteus Latest version: V1.0 (November 2026, this tutorial) Other component libraries: C945 Transistor · PC817 Optocoupler · Relay Module · Resistor · 5 mm LED · Designer Colour LED · Push Button · Active Buzzer · Electrolytic Capacitor · ...