This circuit works as both an injector and a signal follower. We found it in the May 1994 issue of Electronics Now. The Z1 headphone must be high impedance.
This circuit was found in 1980s American documentation. The transducer is a piezoelectric capsule and the...
This circuit from the 80s uses an integrated circuit from the time. The CI is difficult to find...
This receiver, which, depending on the coil, can receive medium or short waves, was found in a...