1. Bob Pease built this varactor-input op-amp out of discrete components, based on an old design of Jim Williams. A varactor bridge input lowers the input bias current below a picoampere.

Researchers at University College London (UCL) recently developed a new varactor based on materials that exhibit quantum paraelectric behavior. Their proposed device, introduced in a paper ...

Here are a number of alternative ways to avoid problems when driving Varactor Diodes. Varactor (or “varicap”) diodes are used primarily in radio-frequency (RF) circuits to provide a ...

How does a varactor diode work? To form the PN junction that makes a diode, half the piece is doped with a trace amount of “donor atoms” that have one more electron than the intrinsic stuff to make ...

There is no traditional main tuning capacitor. Instead a 1SV149 varactor provides the radio’s main tuning capacity (the diode tunes between 35 to 500 pF). The post provides a nice design and ...