Using a 4046 PLL, which is not very common nowadays, this circuit was found in the October 1994 issue of Electronics Now magazine. The power is provided by the transistor and is small in this case.
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...