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 with two transistors was found in Radio Electronics magazine from March 1963. The V2...
By connecting several photocells in series, we can directly activate a sensitive relay, as shown in...
The TDA7052 is a complete 1W integrated amplifier that requires only one capacitor and an external...