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 80's circuit has an input resistance of the order of 880 M and gain 10, using operational...
We found this circuit in the Audio Handbook of the National Semiconductor of 1977. The circuit is used...
Published in 1988 in Hands-On Electronics, this circuit converts the 12 V of a battery into 120 V...