This circuit was found in a 1965 Electronic Design. What it does is respond only to positive pulses (above zero volts) and can be used in automation systems.
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...