This circuit was found in a Popular Electronics from the 90s. The transistors are general purpose, and the gain depends on the ratio between R2 and R1.
The idea of this circuit is to press the button in such a way that the flow of the LED in the...
This signal injector and tracer (follower) was found in an old American documentation. The...
This small signal generator for the bench was found in a 1988 documentation. The signals are...