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.
of the National Semiconductor of 1994. The same technique can be used with other operators and the...
This is an interesting configuration of the LM317 voltage regulator found in an EDN from the 90s....
This circuit is from the datasheet of STMicroelectronics, being indicated for the voltage...