This 6-transistor circuit had excellent sensitivity using germanium transistors. The push-pull stage used two transformers, one drive and one output as we usually find at the time.
We found this circuit in the April 1975 Radio Electronics magazine. The circuit has a latch and...
We found this sophisticated home alarm in a 1994 documentation. The circuit supports sensors of...
This circuit was found in the 1991 Electronics Experimenter's Handbook. It activates a relay when...