Using the name of varactor this circuit was found in the Radio Electronics magazine of July 1982. Varicaps of any type can be used and the components selected according to the component.
The A3906 integrated circuit from Allegro MicroSystems (www.allegro.com) consists of a single-step motor...
We found this circuit in a 1980s publication on telephony. The circuit uses an integrated...
This circuit can use a pendulum sensor. We found this configuration in a 1994 publication. The...