lamaPLC: Multi-channel optocoupled relay module

A multi-channel optocoupled relay module isolates high-voltage AC or DC circuits from low-power microcontrollers using internal infrared optocouplers.

Understanding relay voltage ratings is essential for microcontrollers. For Arduino, 5V/3.3V relays are typical, whereas Raspberry Pi Micro and ESP32/3286 generally require 3.3V relays. These voltage ratings, such as “5VDC” or “3VDC,” are marked on the relays along with the maximum load capacity for AC and DC, for example, 10A at 250V AC or 30V DC, and 12A at 125V AC or 28V DC. In my experience, these maximum values are often overstated; I usually cut them in half. For example, for 240V AC, I consider a safe maximum of 5A, roughly 1000 Watts.

HL-54 (4-channel 3.3V optocoupled relay module)