4-Channel 5V Relay Module (10A, Optocoupler Isolated)

This 4-Channel 5V Relay Module is designed to let low-voltage microcontrollers switch higher-current electrical loads through four independent electromechanical relays. It is widely used with Arduino, AVR, PIC, ARM and similar controller boards where digital output pins cannot directly drive lamps, fans, pumps, solenoids, motors or other appliances. Each relay channel provides a common terminal with Normally Open and Normally Closed contacts, allowing flexible ON/OFF control depending on your wiring requirement. The module operates from a standard 5V DC supply and accepts TTL-level control signals. Optocoupler isolation on the input side helps reduce electrical interference between the microcontroller circuit and the relay driver section, which is especially useful in automation panels and mixed-signal projects. Many 4-channel opto-isolated relay boards also provide jumper-based configuration for high-level or low-level triggering, making them easier to integrate with different controller logic styles. Each relay output is rated up to 10A, suitable for many medium-load switching tasks when used within the relay contact rating and with proper wiring, fusing and electrical safety practices. The board includes input header pins for channel control, power pins for 5V supply, indicator LEDs for relay status and screw terminals for load connection. For mains AC applications, installation should be done only by qualified users with proper insulation, enclosure and strain relief. Typical applications include smart home appliance switching, 4-zone lighting control, pump and valve automation, lab equipment control, robotics power switching, timer-based loads and IoT automation systems. Package includes one 4-channel 5V relay module. Pin names commonly include VCC, GND, IN1, IN2, IN3 and IN4, with each relay output marked COM, NO and NC.