ABCs of Varactors - Rufus Turner - What are varactor / varicap diodes?

Reading time: 2 minute The varactor diode or varicap diode is a special diode that has the characteristic of modifying its internal capacity as the voltage applied to the terminals varies. The advantage of the varivap diode (varactor) over a trimmer or a variable capacitor is that we can make very fine adjustments and we can get even very small capacities.