The circuit is from Ferranti's 1974 transistor manual. Transistors are general purpose types, and the output waveform is rectangular. Components can be changed to other frequencies.
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...