This crystal or galena radio uses a germanium diode. C1 is an old radio variable and L1 has 100 turns of 26 or 28 wire in a 1 inch PVC pipe. The antenna must be a long wire.
In the figure below we have the typical circuit of an automotive star alternator with the...
This simple pass-through circuit was obtained in an old documentation, but it is still up to date...
This circuit was obtained in a 1974 National Semiconductor components and circuits manual. The...