This relay module is 5V active low.Low Active Means Relay will Get Trigger when Low Voltage/Signal Supplied to IN Pin. This Is A 5v 2-Channel Relay Interface Board,Be Able To Control Various Appliances, And Other Equipments With Large Current.It Can Be Controlled Directly By Microcontroller(Arduino , 8051, Avr, Pic, Dsp, Arm, Arm, Msp430, Ttl Logic) 5v 2-Channel Relay Interface Board, And Each One Needs 15-20ma Drivercurrent Equiped With High-Current Relay, Ac250v 10a ; Dc30v 10a The 8550 Transistor Drive, Drive Ability Working Voltage 5 V Has The Fixed Bolt Hole And Easy Installation Standard Interface That Can Be Controlled Directly By Microcontroller( Avr, Pic, Dsp, Arm, Arm, Msp430, Ttl Logic) Indication Led’S For Relay Output Status