This crystal-based circuit can generate accurate 50 or 60 Hz signals. The circuit is from a November 1998 Electronics Now magazine. The output signal consists of rectangular pulses.
This Japanese radio is from the 60s, presenting excellent sensitivity and an output power of 100mW...
Found in a Popular Electronics from the 90s, this circuit uses components that are still current....
This circuit consists of a simple capacitance bridge. The handset can be high impedance from 500...