Machine-translated by Google. Questions are authored in English.
Top

Discussion

The reason a variable capacitor for a radio tuner uses air rather than a solid dielectric is that air

  • A.has a higher permittivity than any solid insulant
  • B.has a much greater dielectric strength than any solid
  • C.gives a larger capacitance for the same plate area
  • D.allows the plates to move without wear or loss

Answer: D

Interleaved vanes must slide past one another repeatedly, which no solid dielectric would survive, and air introduces almost no loss at radio frequency. The penalty is a small capacitance for the volume, which is why such capacitors are physically large for a few hundred picofarads.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.