chapter25 - )dica gnorts a netfo etylortcele dellac yrettab...

Info icon This preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
How do we charge a capacitor? People knew how to make a brief spark, but not how to keep charges moving. Volta invented the battery in 1800’s. - - - - + + + + Liquid or Paste inside battery called electrolyte (often a strong acid) Two metal plates are called electrodes. Battery Device that generates and maintains an electrical potential difference.
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
By using two different metals for the electrodes, we can have two different chemical reactions. The reactions build up charges creating the electrical potential difference between the metal electrodes. One unit is called a “cell”. Many cells put together is called a battery. Example: Car battery is six 2 V cells = 12 V battery Battery Each cell consists of a lead (Pb) electrode and a lead oxide (PbO 2 ) electrode immerse in a solution of water and sulfuric acid (H 2 SO 4 ). The “Mac Gyver” Battery
Image of page 2
EMF When the battery is not connected, the charges have nowhere to go: they feel a potential, but they stay in the electrodes When we “close” the circuit, charges can move, can circulate, producing a “current” http://www.youtube.com/watch?v=F1p3fgbDnkY&NR=1 Analog between a battery and an escalator. --------------------- +++++++++++++ + + + V bat Electro motive force (EMF)
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Charging a capacitor The electrons will flow through the wires. However, they cannot jump through the empty space between the plates. Charges will accumulate in the plates until the potential difference or voltage equals the one in the battery. Electric current 8 = = dt dQ t Q I Rate of flow of charge Units [ I ] = Coulombs/second = Ampere (A) or “Amp”
Image of page 4
Electrons flow in metals, not the protons, so the negative electric charges are moving. -e E E e E q F v v v = = Electrons go “upstream” against the electric field vector. What or “who” is carrying the current? Flow of negative charge in one direction is equivalent to flow of positive charge in the opposite direction.
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    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.

    Student Picture

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

  • Left Quote Icon

    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.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    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.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern