This circuit takes advantage of the sensitivity of the valve to triggering to activate a short-distance relay. We found it in a Radio Craft from October 1947. It is powered by batteries. The frequency depends on the coil.

This circuit takes advantage of the sensitivity of the valve to triggering to activate a short-distance relay. We found it in a Radio Craft from October 1947. It is powered by batteries. The frequency depends on the coil.