Found in an American 1980s documentation, this circuit compares signals from two TTL sources, providing an output that depends on the frequency difference. The circuit can be used as a shield.
This circuit was found in 90s Radio Electronics. The transistor can be any general purpose....
The circuit below shows how to obtain a monostable from a CMOS 4013 flip-flop. The actuation time...
This circuit is from Philips' 60s documentation. The circuit can be applied to modern operational...