This RC relay enables easy control of large, electrically isolated loads in radio control (RC) systems. The activation threshold and direction are configurable, and a safe-start feature reduces the likelihood of unexpected activation. This assembled version ships with the 5V relay, terminal block, and straight male header pins soldered in, so it can be integrated into hobby RC systems without the need for additional soldering. The included power relay is an G5LE-14-DC5 and is rated for up to 10A under most conditions.The RC switch measures the width of incoming RC pulses and compares it to a user-configurable threshold (with ±64µs of hysteresis) to decide whether to turn on the MOSFET. By default, the threshold is approximately 1700µs, with switch activation occurring above the threshold (longer pulses), but the switch has a learning mode that allows you to change the threshold and the activation direction. A safe-start feature reduces the likelihood of unexpected activation. We generally recommend using a 4- or 5-cell NiMH or NiCD battery pack to power the switch. The battery pack will typically be connected to an RC receiver or servo controller, which passes the power on to the RC switch. The board has four mounting holes that work with #2 or M2 screws (not included).