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.
Found in a 1980’s documentation, this circuit must have its signal applied to an amplifier stage. The...
We show only one of the channels of an excellent audio preamplifier with the LM382 integrated...
This circuit is from 1983 documentation. The author shows us an experimental circuit of a siren...