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 is indicated for measurement bridges as a null detector, thanks to the logarithmic gain...
This circuit, of a Popular Electronics of 1969 is destined to firing a gas LASER of the time. The...
This bass booster preamp is from an English publication (1966). We can mount it with more modern...