This is a 5V, 10A 2-Channel Relay interface board. It can be used to control various appliances, and other equipments with large current. It can be controlled directly with 3.3V or 5V logic signals from a microcontroller (Arduino, 8051, AVR, PIC, DSP, ARM, ARM, MSP430, TTL logic).

It has a 1x4 (2.54mm pitch) pin header for connecting power (5V and 0V), and for controlling the 2 relays.

The pins are marked on the PCB:-

• GND - Connect 0V to this pin.
  
• IN1 - Controls relay 1, active Low Relay will turn on when this input goes below about 2.0V
  
• IN2 - Controls relay 2, active Low Relay will turn on when this input goes below about 2.0V
  
• VCC - Connect 5V to this pin. Is used to power the opto couplers

Specification:-

• High current relay, AC250V 10A, DC5V 10A
  
• 2 LEDs to indicate when relays are on
  
• Works with logic level signals from 3.3V or 5V devices
  
• Opto isolation circuitry