Found in a publication by Gernsback from 1960, this circuit uses germanium transistors of the time and commercial coils. It can be changed to operate with modern transistors and other wavebands.
This source is used to supply circuits with operational amplifiers, being originally created for...
The transistors in this 80's documentation project may be BC548, the most modern equivalents of...
This circuit uses a FET to drive an LED with constante currente. The current up to 20 mA can be...