The Arduino Relay Shield allows your Arduino driving high power loads. It is a solution for driving high power loads that cannot be controlled by Arduino's digital IOs, due to the current and voltage limits of the controller.The Shield features three relays, each relay provides 2 pole changeover contacts (NO and NC); in order to increase the current limit of each output the 2 changeover contacts have been put in parallel.Three LEDs indicate the on/off state of each relay.PowerThe shield can be powered by external power: External power can be used by connecting the DC Jack input with required voltage [recommended voltage is 5V]. You will have to connect the jumper to EXT in JP1. To drive the relays with 5V from arduino you can connect the jumper to INT in JP1.Input and OutputThe relays are controlled by the following Arduino board pins: Relay 1 = Arduino pin 2Relay 2 = Arduino pin 3 Relay 3 = Arduino pin 4
