This circuit uses a transistor to trigger the alarm from a low quiescent current sensor. The relay is 12 V. The circuit is from Radio Electronics magazine, April 1975.
We found this circuit in a 1978 publication. The flip-flops are of the T type and the time...
This circuit generates a signal up to a few megahertz depending only on the LC resonant circuit...
This simple receiver with germanium transistor and listening on a crystal phone was discovered in a...