Found in 1965 Delco Radio documentation, this circuit uses transistors from that era. Modern equivalents can be used. The characteristics of the inductor were not given.
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...