This simple two-transistor FM transmitter was found in the November 1991 issue of Radio Electronics magazine. The circuit has a 2 + 2 turn coil of 28-gauge wire with a diameter of 1 cm.
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...