We found this circuit in the August 1994 issue of Electronics Now magazine. The circuit is based on the now uncommon CMOS 4046. The frequency range is given by C1.
This very simple circuit must use coal microphones of the type found in very old equipment. The...
This biestable circuit was found in a Popular Electronics from the 90s. The circuit has an unusual...
This circuit was found in a 1969 US documentation. It provides a signal that can be externally...