With this circuit, a relay can be activated from an alternating signal with frequency up to a few tens of kilohertz. The transistors can be the BC548. The circuit was obtained from Radio Electronics in July 1990. The power supply must be isolated.

With this circuit, a relay can be activated from an alternating signal with frequency up to a few tens of kilohertz. The transistors can be the BC548. The circuit was obtained from Radio Electronics in July 1990. The power supply must be isolated.