1 / 26

PHYSICS 51 CH 30.1

PHYSICS 51 CH 30.1. Homework #11: Inductance. Read Ch. 30: Inductance Do Exercises :Ch 30 : 9, 22, 32, 65 HW due 4/29 (next Tuesday). Today. Introduce Mutual Inductance Self Inductance and Inductors Simple LR circuit LC circuit Test Review. SELF - INDUCTANCE.

jamil
Download Presentation

PHYSICS 51 CH 30.1

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. PHYSICS 51 CH 30.1

  2. Homework #11: Inductance • Read Ch. 30: Inductance • Do Exercises :Ch 30 : 9, 22, 32, 65 • HW due 4/29 (next Tuesday)

  3. Today • Introduce • Mutual Inductance • Self Inductance and Inductors • Simple LR circuit • LC circuit • Test Review

  4. SELF-INDUCTANCE An inductor (L) – When the current in the circuit changes the flux changes, and a self-induced emf appears in the circuit. A self-induced emf always opposes the change in the current that produced the emf (Lenz’s law).

  5. Inductors

  6. Voltage across and Inductor Across a resistor the potential drop is always from a to b. BUT across an inductor an increasing current causes a potential drop from a to b; a decreasing current causes a potential rise from a to b. Inductors add like resistors

  7. Inductance • EMF opposes change in current • L in Henrys • Inductors add like resistors • At t = 0 inductors act like open ckts • At t = infinity inductors act like shorts • Energy stored is U = ½ Li2

  8. Example R1 R2 L1 = L2 = 0.020 H L2 V=10V L1 R1 = R2 = 0.50W For the circuit shown Initial current through the resistor Final current through the resistor Energy stored by indictors at final current Current after 0.01s Voltage across inductors after 0.01s S

  9. LC Circuit Oscillation in an LC circuit. Energy is transferred between the E field of the capacitor and the B field of the inductor.

  10. Oscillation in an LC circuit. Energy is transferred between the E field and the B field.

  11. Oscillating LC circuit oscillating at a frequency w (radians / second)

  12. PHYSICS 51 CH 30.1

  13. Today • Keep talking about Inductors • Simple LR circuit again • LC circuit • Quiz

  14. Homework #11: Inductance • Read Ch. 30: Inductance • Do Exercises :Ch 30 : 9, 22, 32, 65 • HW due 4/29 (next Tuesday)

  15. SELF-INDUCTANCE An inductor (L) – When the current in the circuit changes the flux changes, and a self-induced emf appears in the circuit. A self-induced emf always opposes the change in the current that produced the emf (Lenz’s law).

  16. Inductance • EMF opposes change in current • L in Henrys • Inductors add like resistors • At t = 0 inductors act like open ckts • At t = infinity inductors act like shorts • Energy stored is U = ½ Li2

  17. Voltage across and Inductor Across a resistor the potential drop is always from a to b. BUT across an inductor an increasing current causes a potential drop from a to b; a decreasing current causes a potential rise from a to b. Inductors add like resistors

  18. (a) A decreasing current induces in the conductor an emf that opposes the decrease in current. (b) An increasing current induces in the inductor an emf that opposes the increase. (Lenz’s law) c.Physics, Halliday, Resnick, and Krane, 4th edition, John Wiley & Sons, Inc. 1992.

  19. A resistor is a device in which energy is irrecoverablydissipated. Energy stored in a current-carrying inductor can be recovered when the current decreases to zero and the B field collapses. Power = energy / time P = i 2 R (time)

  20. Example During an R-L circuit decay, How much energy is lost after one time constant

  21. Inductor for Exercise 30-7.

  22. LC Circuit Oscillation in an LC circuit. Energy is transferred between the E field of the capacitor and the B field of the inductor.

  23. Oscillation in an LC circuit. Energy is transferred between the E field and the B field.

  24. c.Physics, Halliday, Resnick, and Krane, 4th edition, John Wiley & Sons, Inc. 1992.

  25. Oscillating LC circuit oscillating at a frequency w (radians / second)

  26. Example A radio tuning circuit consists of a fixed 10.0 mH inductor and variable capacitor. What capacitance do I need to tune to in order to receive the Warriors on the radio tonight? KNBR = Warriors = 680 kHz

More Related