This circuit was found in the August 1994 issue of Electronics Now magazine. The 4046 is uncommon these days and the frequency range is given by C1.
This 2004 circuit is based on the ionization effect that occurs in old incandescent lamps with...
This circuit memorizes through an LED indicator if your phone was used during your absence. The...
Found in a 1969 Electronics World, this circuit generates low frequency signals with two...