We found these circuits in a 90s Radio Electronics. In them, we have the way to turn a load on and off using pressure switches. The circuit can be used with other types of direct current load.
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...