This small transmitter appeared in the March 1989 issue of Radio Electronics magazine. The two-transistor circuit used an electret microphone and had a range of a few dozen meters.
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...