5V relay module for switching mains voltage devices. It lets you control 120-240V appliances such as fans, lamps, heaters and other household devices using a 5V logic signal from Arduino or similar microcontrollers. Key features - Real high quality relay with exposed terminal interfaces; maximum load AC 250V 10A, DC 30V 10A. - SMD optocoupler insulation protects the control circuit from relay coil current; strong driving capability and stable performance; trigger current 5 mA. - Easy wiring with terminal blocks for direct connections. Applications and use scenarios - Use with Arduino or other 5V controllers to switch a lamp or a fan based on sensor input or scheduled logic. - Auto control a heater or space heater in a DIY smart home setup with proper safety and isolation. - Build a small automation box to remotely switch multiple AC appliances via a wireless module and the relay board.