This circuit uses an MW radio tuned to around 540 kHz to detect atmospheric signals, for example, from an approaching storm. The circuit was taken from a Popular Electronics from the 90s.
This circuit is the conventional use of the 7805 as a constant current source up to 1 A. The...
The integrated circuit used in this application is not currently common. The circuit is from an...
This circuit is from a Radio Electronics from February 1966. The circuit is of a type that was...