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 integrated circuit used is no longer very common today, but there are still many sources that...
Common general purpose silicon diodes when direct biased provide a voltage fall of about 0.6 to...
This alarm with the 555 integrated circuit is from an EDN from the 90s. The circuit directly...