With this circuit, signals in the range of 10 kHz to 150 kHz can be received at close to 4 MHz from a shortwave receiver. The circuit is from a 303 Circuits from the 90s.
This amplifier for automotive use was found in the SGS manual of linear integrated circuits of...
This circuit was found in documentation from the 70s. We can try current JFET transistors....
This circuit makes use of a thermometric sensor that heats or cools according to a current of air....