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 current-limited circuit was found in a Popular Electronics from the 90's. ...
In this interesting circuit, a common relay is used as a vibrator to obtain high voltage with a...
Nixie-type displays are no longer used except for assemblies of people who like old technology. The...