Found in a 1924 Gernsback publication this circuit uses 4 batteries for power and loop antenna. Listening is over a high-impedance type earphone or loudspeaker common at the time.
This circuit allows the measurement of resistance in the megohms range using an indicator LED and...
The purpose of this circuit is to enable the car or motorcycle starting system only for a certain...
With this circuit it is possible to receive signals in the 2 m (150 MHz) range on a pocket AM...