The radios described here are a regenerative design utilizing a single JFET and cheap audio amplifier integrated circuit.
(JFET: “Junction Field Effect Transistor”, a small electronic device which can amplify radio signals and is used as the basis for these radios.
Regenerative: employing “regeneration” (feedback), a technique used in simple radio designs to increase the amplification of radio signals.)
Here in Taiwan, there don’t appear to be many people dabbling in radio as a hobby. My recent experiments with simple radios that students might be able to make, have been regarded somewhat like “black magic”. So it hasn’t been too difficult to get students interested in it and a few of them have made the radios described below with very good results.