Pololu

Relay modules that accept low‑voltage control signals and switch higher‑power or isolated loads are essential for robotics, automation and embedded projects. They provide solid‑state or electromechanical switching, allowing a microcontroller to turn motors, lights, actuators or radio‑control devices on and off without exposing the control circuit to the load voltage. Typical boards include single‑pole‑double‑throw (SPDT) carriers for “sugar‑cube” relays, dual‑channel versions, and isolated solid‑state switches that respond to a 2.7 V–40 V input. Key attributes are reliable isolation, straightforward wiring via terminal blocks or JST connectors, and compatibility with common development platforms. The compact form factor and clear pin‑out make integration simple, while the ability to handle 5 V or 12 V coil voltages offers flexibility for a range of power‑handling requirements.