This 1970 Electronic Design circuit uses a varactor or varicap. The circuit divides the frequency of a 150 MHz signal by 2. Similar versions appear on this site.
The circuit shown in the figure shuts off a load when the voltage drops below the value determined...
This oscillator can run in frequencies up 10 MHz depending on the Power supply voltage. The 1 µF...
This circuit was obtained from an American technical manual from the 80's. The integrated circuit...