This simple audio signal tracer or follower can be made with a BC548 instead of the original transistor. The output is made in a small crystal phone. The power can be from 5 to 9V.
This circuit was found in an American documentation from the 1980s. The circuit combines filters of...
In the figure we have a basic double T filter with components that must maintain a specific range...
The load used in this experimental circuit is a small incandescent lamp but it can be replaced by...