This circuit was obtained in an American documentation from the 80's. The transistors can be equivalent to those indicated and the crystal can reach a few tens of megahertz.
This circuit receives the local stations of medium waves listened to in a piezoelectric capsule or...
This circuit was published in an 80's American documentation, but it is still current. The power...
This simple neon lamp power indicator circuit was found in the January 1971 Radio Electronics...