This converter for WWV time reference station signals was found at Popular Electronics. The 15 MHz signals are now received on a medium wave radio at 1 MHz.
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....