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

The RELAY-8CH is an eight-channel relay interface board that allows low-voltage microcontrollers to switch high-power electrical loads safely and independently. Each of the eight 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.

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 draws approximately 15–20mA 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 active low relay module exposes all relay contacts through screw terminals, with NO (Normally Open), COM (Common), and NC (Normally Closed) connections available for each channel. Input connections are provided on a separate header for VCC, GND, and IN1–IN8. A JD-VCC jumper allows the relay coil supply to be separated from the logic supply, enabling an external power source for the relays when driving heavy loads. The module measures approximately 138 × 56 × 19.3mm and includes four 3.1mm mounting holes, making it suitable for panel or DIN-rail mounting in control cabinets. It is a passive switching board—it does not include a microcontroller, wireless interface, or enclosure.