This circuit with the LM741 operational amplifier can be applied to other operational amplifiers. We found it in the September 1989 Radio Electronics magazine.
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...