This old circuit from the 80's generates logic signals with 50% active cycle (squares). The integrated circuit used is not common today, but equivalent logic functions can be used in a modern version.
This circuit was obtained from a Hands-On Electronics, an American magazine from January 1987. The...
This receiver for listening to the TR-23 phone was manufactured in Japan in the 1960s. The circuit is...
This astable multivibrator with an operational one at the time was found in the National...