There are 5V, 12V, or 24V relay options on the bottom of this page. The default relays shipped with this product are 5V.

Description:

Powered by the ULN2003 high current driver, this module gives you easy control of up to 7 relays using TTL logic from an Arduino, Beagle Bone, or Raspberry Pi. 5V, 12V, and 24V relay options.

Hookup:

• Vcc: Coil Voltage (if you are using a 24V coil, hook 24V up here, its what powers the coil and pulls in the contact)
• In: (7 Inputs) TTL input from microcontroller (can be 3.3V or 5V input, it will be what causes the coil to pull in)
• GND: Ground. This must be a common ground with the TTL in and the Coil Vcc power.

• COM: (7 outputs) Common side of relay contact. Acts as a switch. Rated at relay ampacity.
• NO: (7 outputs) "Normally Open" side of relay contacts. Acts as a switch. Normally Open. When coil is energized, the contact will change state and close. Rated at relay ampacity.
• NC: (7 outputs) "Normally Closed" side of relay contacts. Acts as a switch. Normally Closed. When coil is energized, the contact will change state and open. Rated at relay ampacity.
• Currently the NO and NC labels on this board's outputs are reversed. This will be fixed in a future iteration.

Features and Specifications:

• Relay control is simple TTL level digital signals.
• 7 DPDT output relays.
• Signal and power indicator LEDs

• Relay Coil Voltage: 5V, 12V, or 24V (select in options below).
• Relays: 7
• Relay Type: SPDT

Documentation and Support:

• Schematic