This 1-channel 5V control Single-Pole Double-Throw (SPDT) AC power relay board can be controlled directly via a microcontroller and switch up to 10 amperes at 250 VAC. Inputs are isolated to protect any delicate control circuitry.
The default state of the relay when the power is off for COMM (power) to be connected to NC (Normally Closed). This is the equivalent of setting the relay board IN pin to HIGH (has +5v sent to it).
When you have power connected to the relay's NO (Normally Open) connector and you set the corresponding IN pin to LOW (0V, or Ground), power will flow in from the COMM connector and out of the NO connector powering your device.
Specifications:
Polarity: Active Low - you must ground the control input to switch this device ON
Relay Max Switching Voltage: 250 Volts AC
Relay Max Switching: Current: 10 Amps AC
Relay Control Voltage: 5.0V directly via microcontroller (Arduino, AVR, PIC, ARM, BoardX, Raspberry Pi, MSP430, etc)
Relay Control Current: 20-30 mA
Indicators:
Red LED illuminates when +5V VCC control power is applied to the board.
Green LED illuminates when control pin is pulled low (relay is activated).

Size: 42mm x 17mm x 17mm (1.65 x 0.67 x 0.67 inches) L x W x H