PC817 4-Channel Optocoupler Isolation Module

Connecting two circuits running at different voltages, or a sensitive microcontroller to anything with real electrical noise (motors, relays, industrial equipment), risks damage or interference unless the two sides are electrically isolated. Each of this module's four channels uses a PC817 optocoupler to bridge that gap with light instead of a direct electrical connection - an LED on one side, a phototransistor on the other, with no electrical path between them at all.

Jumper-selectable pull-up or pull-down configuration per channel gives flexibility in matching the logic convention of whatever's on the other side, and the wide 3.6V to 24V input/output range covers everything from 3.3V microcontroller logic up to 24V industrial control signals. Because all four channels operate independently, one board can isolate multiple signals at different voltage levels simultaneously rather than needing a separate isolator per signal.

Common uses are isolating a microcontroller from motor driver or relay boards that generate electrical noise, bridging mixed-voltage control signals (3.3V logic to 24V industrial equipment), and general signal isolation anywhere two circuits shouldn't share a direct electrical ground reference.