Pololu Basic 2-Channel SPDT Relay Carrier with 5VDC Relays (Assembled)

Description

The carrier board routes the relay control pins to 0.1?-spaced pins compatible with standard solderless breadboads and female servo cable connectors. The assembled version of this board has all seven control pins populated with 0.1? straight male headers while the partial kit version includes 25×1 straight and 15×1 right angle 0.1? male header strips that can optionally be broken into pieces and soldered in. The relay switch pins are routed to a set of large pads intended for use with two 3-pin 5mm-pitch terminal blocks and a set of smaller pads with a 0.2? pitch, making them compatible with 0.1? perfboards. The assembled version of this board has the terminal blocks soldered to these pins while the partial kit version includes 6-pin terminal blocks that can be optionally soldered in. The carrier board has four mounting holes that work with #4 or M3 screws.

 
Advantages over similar products

Compact layout
LEDs to indicate coil actuation
Zener diodes for fast current decay on relay coils
Specification of electrical routing clearance rules on relay switch nodes

The switch portion of the relays are accessible on one side of the board while the control pins are routed to the other. The relay coils are powered by supplying 5 V or 12 V across the VDD and GND pins (depending on the relay), and they are activated by digital high control signals on their respective EN pins. The control signals are fed directly to the BSS138 N-channel MOSFETs, which in turn actuate the relay coils when the signal voltage exceeds approximately 2.5 V (see BSS138 datasheet (92k pdf) for details). The control pins are arranged to allow for several connection options: a single 1×4 cable can be used to supply coil power and the two control signals, or two 1×3 cables (such as servo cables) can be used side-by-side (one for each relay).

The relay switch terminals COM (common), NO (normally open), and NC (normally closed) are routed on the PCB with a minimum clearance of 60 mils (1.5 mm) from other copper and the edges of the board, though manufacturing variations in the board edges can make those distances slightly lower.

In most applications, the current and voltage ratings for the module will match the ratings of the relay used. Maximum current, maximum voltage, and life expectancy are interdependent; we therefore recommend careful examination of your relay’s datasheet.