This circuit is the receiver for the previous transmitter modulated by an audio signal. The transducer is a ceramic capsule, in which case the circuit becomes ideal for telegraphic transmissions.
Several versions of this circuit can be found on this website. This makes use of FETs that can...
The circuit shown was found in the February 1994 issue of Electronics Now magazine. The circuit...
Found in American documentation from the 1980s, this circuit makes use of components of the time,...