capacitances gives the result for the series case L L L 2 1 2 2 1 1 2 1 1 1 1 C

# Capacitances gives the result for the series case l l

This preview shows page 13 - 21 out of 23 pages.

capacitances, gives the result for the series case: L L L + + = + + = + + = 2 1 2 2 1 1 2 1 / 1 / 1 / 1 / / / C C C C q C q C q V V V tot tot tot tot
Results for Capacitor Combinations Capacitors in parallel: L + + = 2 1 C C C tot Capacitors in series: L + + = 2 1 / 1 / 1 / 1 C C C tot
Example: Problem 25-8 What is effective capacitance of the device?
C 12 F C F C F C μ μ μ 0 . 4 0 . 5 10 3 2 1 = = = F C C C C μ 3 . 3 3 / 10 10 / 3 5 / 1 10 / 1 / 1 / 1 / 1 12 2 1 12 = = = + = + = F C C C tot μ 3 . 7 4 3 . 3 3 12 = + = + =
Dielectric Materials Applied electric field polarizes material This produces an induced surface charge This reduces field within material This reduces potential difference This increases capacitance Effect of placing a dielectric between the plates of a charged capacitor:
E=0 electron nucleus Polarization of atoms and molecules Non-polar molecules: induced dipoles Polar molecules: preferential orientation
Dielectric materials Dielectric materials polarize under external electric field E 0 Polarization creates the opposing electric field: –E’ Total field E=E 0 -E =E 0 / κ < E 0 κ is called dielectric constant It shows how the field in a dielectric is weaker than in vacuum
Dielectric Constant So the effect of a dielectric is to decrease the field and increase the capacitance.

#### You've reached the end of your free preview.

Want to read all 23 pages?

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern