Octal Relay Board (RELAY8)
RELAY8 Octal Relay Board with Terminal Blocks, Unpopulated 2 Sided PCB, 3U Size (100 x 160 mm)


  • A bare PCB to build a relay board with 8 DPDT relays.  Each relay has up to four 3-pin terminal blocks to connect to the relay contacts.
  • Can be controlled via an I2C interface or 8 logic lines.  UEXT connector used for I2C connection.
  • Can be used with 5V, 9V or 12V Omron G5V series relays with 2 Amp contacts.  The supply voltage must match the relay voltage.  Separate logic supply required for I2C.
  • Bare PCB only (unpopulated, no parts provided).  BOM and schematic available for download.
  • Mostly thru-hole construction allows for easy assembly (I2C output port is SMT).
  • Double-sided, FR4 glass-epoxy PCB, 1oz/ft2 copper, anti-tarnish coating. Soldermask & silkscreen.  Lead free and RoHS compatible.

The RELAY8 is an output board providing 8 DPDT relays for microcontroller projects. Each relay has two switches with NO and NC contacts (Normally Open and Normally Closed).

Removable 5.08mm (0.2 inch) terminal blocks are used to connect circuitry to the relays. Each relay has two switches, and each switch has two 3-pin terminal blocks that can be installed to provide an easy way to connect multiple wires to each contact.

The RELAY8 board can be built to be controlled by 8 logic signals or an I2C interface. A 2x8 header is used to connect to the inputs with a 16-pin ribbon cable for the logic level version. An Olimex style UEXT 2x5 header is used for the I2C option. UEXT is an open standard developed by Olimex providing 3 Volt I2C, SPI, and USART expansion on one connector. A 10-pin ribbon cable is used to connect to dev boards with UEXT connectors.

The power input connector can be a coaxial barrel connector, a 2-pin terminal block, or a 2-pin MTA-100 connector, or 0.1" spacing header.

This is an unpopulated board and no parts are included. The BOM (bill of materials) and schematic diagram are available below to construct the circuit. Soldering is required and prior experience with electronic assembly is recommended. A PCB soldermask helps prevent solder bridges on tracks and a silkscreen legend provides part locations. Mostly thru-hole construction allows for easy assembly, maintenance, and modification.


PDF - 800KB

PDF - 221KB
Where to Purchase: