1 / 15

Where Does Current Come From?

Where Does Current Come From?. The free electrons in a conductor need to be replaced when they move through the conducting medium (the wire). These electrons are replaced by electrons from a source of energy such as a battery. Circuit Components. Batteries. +. +.

gili
Télécharger la présentation

Where Does Current Come From?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Where Does Current Come From? • The free electrons in a conductor need to be replaced when they move through the conducting medium (the wire). • These electrons are replaced by electrons from a source of energy such as a battery. EGR 101

  2. Circuit Components • Batteries + + EGR 101

  3. Source of Voltage in a Battery • A chemical reaction within the battery separates positive and negative ions(charged atoms) • When the battery is connected to a circuit, the negative charges move toward the positive terminal and a current is produced • The amount of current is constrained by the resistance of the circuit EGR 101

  4. Example of A Battery The source of energy E in (Joules) releases charges Q in (Coulombs) Voltage (V) – the difference in potential that uses E = one Joule (J) of energy to move a charge Q = one coulomb (C). EGR 101

  5. Current Direction We will adopt “Conventional Flow” for all of our work! EGR 101

  6. Mathematical Relationship • E: Energy required to move charges in Joules (J). • Q: Charge value in Coulombs (C). • V: Voltage or potential difference across the battery's posts in volts (V). • Thus, V = E / Q. • In units: 1 Volt = 1 Joule/Coulomb EGR 101

  7. Team In-class Activity (15 minutes) • A 10 V source uses 2 Joules of energy per second. Calculate the current being used by the source. • Hint, turn the word problem into equations; write down what you know. EGR 101

  8. When batteries are connected with their polarities in the same direction, they are in a series-aiding arrangement. EGR 101

  9. When batteries are connected with their polarities in the opposite direction, they are in a series-opposing arrangement. EGR 101

  10. In Class Activity • What is the total voltage between terminals A and B in the figure below?Which terminal is at a higher potential? A B 9V 4V 15V EGR 101

  11. Introduction to Ohm’s Law • A 1 Ohm resistance limits the current to 1 Amp when 1 Volt is applied. V = I.R EGR 101

  12. Ohm’s Law • Three forms: • Use the form that best describes the quantity that you are trying to determine EGR 101

  13. Determine the Current I + _ EGR 101

  14. Determine the Voltage + _ EGR 101

  15. Determine the Resistance + _ EGR 101

More Related