This circuit detects changes in the active cycle of the input signal. The circuit was obtained in a 1966 EEE. Transistors are general purpose types of the time.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...