4 Channel 5V Relay Module

The 4 Channel 5V Relay Module is a compact relay breakout board designed to switch four independent electrical loads using low-voltage digital signals. It is one of the most popular modules for Arduino automation, Raspberry Pi control panels, IoT projects and embedded system prototypes where a microcontroller needs to operate devices such as lights, motors, valves, fans or buzzers. Each channel has a mechanical relay with screw-terminal contact outputs, allowing connection to normally open or normally closed circuits depending on the project requirement. The board works by using a 5V supply to energise relay coils through onboard driver circuitry. A control signal applied to IN1, IN2, IN3 or IN4 activates the corresponding relay, physically changing over the COM, NO and NC contacts. This provides electrical separation between the low-voltage control side and the higher-power load side. Many 4-channel relay boards of this type include optocoupler isolation, indicator LEDs and a VCC/JD-VCC jumper arrangement for cleaner separation of logic and relay power when required. With a typical contact rating of up to 10A at 250VAC or 10A at 30VDC, this 5V relay module is suitable for a wide range of switching applications, provided the load is within the relay rating and proper safety practices are followed for mains wiring. The board size is approximately 73–75mm x 54–55mm x 19–20mm, making it easy to mount inside project enclosures, automation panels or robotics chassis. Typical pin connections include VCC, GND and four logic inputs IN1–IN4 on the control header. Each relay output provides COM, NO and NC terminals. Use a stable 5V supply with sufficient current capacity, especially when multiple relays are switched on at the same time. Package includes one 4 Channel 5V Relay Module. Connecting mains voltage should be done only by qualified users with suitable insulation, fusing and enclosure protection.