This TTL circuit was found in the December 1990 issue of Radio Electronics magazine. The circuit has a 50% duty cycle. It must be powered by 5 V.
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...