When the power is cut off, this circuit keeps the flashlight on for a while, allowing it to be located. The circuit is from a Radio Electronics from September 1992.
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...