1 / 41

Chapter 22 – Alternating Current Part 1

PHY-2054 J. B. Bindell. Chapter 22 – Alternating Current Part 1. No problem session on Monday (Not much to do!) Watch for a Mastering Physics Assignment Quiz next Friday on AC … will it ever end? Today we start AC Circuits We will review the exam when they are returned.

bandele
Télécharger la présentation

Chapter 22 – Alternating Current Part 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. PHY-2054 J. B. Bindell Chapter 22 – Alternating CurrentPart 1

  2. No problem session on Monday (Not much to do!) Watch for a Mastering Physics Assignment Quiz next Friday on AC … will it ever end? Today we start AC Circuits We will review the exam when they are returned. Upcoming items for your consideration

  3. Exam STructure

  4. We will retain this schedule. If something else is going on in the room, come to my office! If I am not there …. come to my office.

  5. Easy OK Difficult Impossible OK … How was the test?

  6. great less than stellar ok poor bombed How did you do?

  7. better than last time about the same as last time worse than last time This time I did

  8. ac generator

  9. “Output” from the previous diagram

  10. Nuclear

  11. DC /AC

  12. home generators FUEL

  13. what works on ac? EVERYTHING!

  14. AC -All is “in-phase”

  15. But not always! (capacitor)

  16. Let’s talk about phasey=f(x)=x2

  17. y=f(x-2)=(x-2)2 y x2 (x-2)2 2 x

  18. f(x-b) shift a distance b in the POSITIVE direction f(x+b) shift a distance n in the NEGATIVE direction. The signs switch! the “rule”

  19. The Sine

  20. Let’s talk about PHASE f(t)=A sin(wt) A=Amplitude (=1 here) f(t)=A sin(wt-[p/2]) A=Amplitude (=1 here)

  21. For the future

  22. AC Applied voltages This graph corresponds to an applied voltage of V cos(wt). Because the current and the voltage are together (in-phase) this must apply to a Resistor for which Ohmmmm said that I~V.

  23. phasor

  24. oops – the ac phaser

  25. the resistor

  26. Phasor diagram Pretty Simple, Huh??

  27. here comes trouble …. We need the relationship between I (the current through) and vL (the voltage across) the inductor.

  28. From the last chapter: HUH??* * unless you have taken calculus.

  29. check it out---

  30. so- cancel When Dt gets very small, cos (wDt) goes to 1. ??

  31. this leaves The resistor voltage looked like a cosine so we would like the inductor voltage to look as similar to this as possible. So let’s look at the following graph again (~10 slides back): f(t)=A sin(wt) A=Amplitude (=1 here) f(t)=A sin(wt-[p/2]) A=Amplitude (=1 here)

  32. result

  33. Resistor inductor (wL) looks like a resistance XL=wL Reactance - OHMS comparing

  34. slightly confusing point We will use the CURRENT as the basis for calculations and express voltages with respect to the current. What that means?

  35. back to the phasor thing

  36. What about the capacitor?? Without repeating what we did, the question is what function will have a Df/Dt = cosine? Obviously, the sine! So, using the same process that we used for the inductor,

  37. capacitorphasordiagram

  38. The voltage lags the current by 90 deg I and V are represented on the same graph but are different quantities. NOTICE THAT

  39. SUMMARY

More Related