This low power circuit for the FM band was found in a spy book from the 90s. The tunnel diode is not an easy component to obtain and the power can be supplied with a single button cell.
The existence of field effect transistors at the input of the integrated circuit (operational...
This circuit using current components was found in an old documentation. It is a sequential circuit...
In the figure we have a signal detector using a tunnel diode. The circuit is from a Radio...