For those who enjoy building radio projects, you may have noticed that variable capacitors are not as available as they once were. There was a time when all radio receivers contained at least one, but ...

If you’ve seen a big air-variable capacitor, you may have noticed that some of the plates may have slots cut into them. Why? [Mr Carlson] has the answer in the video below. The short answer: you can ...

Variable capacitors may be useful, but the air gap that provides their capacitance is their greatest weakness. Rather than deal with the poor dielectric properties of air, some high-end variable ...