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.
This simple circuit is from a Radio Electronics from July 1965. The circuit can be assembled with...
Found in the May 1975 issue of Radio Electronics magazine, this circuit turns on after a certain...
We found this circuit in a 1965 General Electric documentation. The circuit generates synchronized...