Based on Radio Shack 276-137, this circuit was found in the December 1995 issue of Electronics Now magazine. The circuit drives an LED but could use a relay instead.
In the figure we have the way to use a 4017 as a sequencer controlled by a microcontroller. With...
This oscillator was found in the September 1984 issue of Radio Electronics magazine. The frequency is...
This circuit drives an old tape recorder when an audio signal is received. The circuit is...