16-Channel 5V Relay Module – 10A 250VAC/30VDC, Optocoupler Isolation, Active Low

The RELAY-16CH is a professional-grade, sixteen-channel relay interface board that allows low-voltage microcontrollers to switch high-power electrical loads safely and independently. Each of the sixteen channels provides a Single-Pole Double-Throw (SPDT) relay output rated for 10A at 250V AC or 10A at 30V DC, making the module suitable for controlling lamps, fans, motors, pumps, solenoids, and household appliances from an Arduino, AVR, ARM, PIC, 8051, PLC, or similar logic platform. The board is designed as a PLC expansion output and appliance control module, and it supports independent on/off switching for any of the 1–16 channels.

A key safety feature is per-channel optocoupler isolation, which electrically separates the microcontroller side from the relay coil and load side. This prevents high-voltage transients and ground loops from damaging the host controller and improves noise immunity in industrial environments. Each channel requires approximately 15–20mA of driver current at 5V, and the board includes status LEDs that illuminate to indicate when a relay is energized. The module is configured for active-low triggering: pulling an input pin to logic 0 (LOW) activates the corresponding relay, while logic 1 (HIGH) deactivates it. This behavior must be considered in firmware to avoid inverted switching logic.

The 5V relay module optocoupler integrates an LM2576 step-down power regulator, which means it does not require an external power supply module. The JD-VCC and VCC terminals are separated for full isolation, allowing the relay coil supply to be separated from the logic supply when driving heavy loads. All relay contacts are exposed through screw terminals, with NO (Normally Open), COM (Common), and NC (Normally Closed) connections available for each channel, and each COM terminal is independent for flexible signal access. The module measures approximately 180 × 90 × 20mm and includes four mounting holes for panel or DIN-rail installation. It is a passive switching board—it does not include a microcontroller, wireless interface, or enclosure.