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.
This independently charged circuit was found in a 1969 EEE. The operational amplifier supports a...
This high current regulator for TTL circuits was found in an old French documentation from the...
This indicator was found in a 1974 publication, but it can be fitted with the BC548 transistor or...