This circuit was found in an old American publication. The transformer is the type of output found in old transistor radios. The transducer is crystal headphone.
This circuit was found in an old publication from 1989 but can still be assembled today with BD135...
We found this circuit in a 1987 documentation. Its purpose is to turn on a garage light using the...
In the figure we have a simple logic level indicator for TTL circuits or powered by 5 V....