This converter was found in the June 1991 issue of Radio Electronics magazine. The circuit uses common circuits at the time and its operating range can be changed.
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...