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.
We found this bench circuit in a Radio Electronics magazine from July 1962. The transistors are...
This circuit is from an 80's documentation. The circuit makes use of a component of the era, the...
This Linear Technology circuit can measure currents from 100 pA to 100 uA. The circuit is from the...