Alternating current
Download
1 / 9

Alternating Current - PowerPoint PPT Presentation


  • 158 Views
  • Updated On :

Alternating Current. 20.5. Alternating Current. Charge flow reverses direction periodically Due to way that power plants generate power Simple circuit. Periodicity. Voltage, Current, and Power fluctuate with time So we usually talk about the averages. Average Power. DC P = IV AC

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Alternating Current' - arella


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Alternating current2 l.jpg
Alternating Current

  • Charge flow reverses direction periodically

  • Due to way that power plants generate power

  • Simple circuit


Periodicity l.jpg
Periodicity

  • Voltage, Current, and Power fluctuate with time

  • So we usually talk about the averages


Average power l.jpg
Average Power

  • DC

    • P = IV

  • AC

    • Pmax = I0V0

    • Pmin = 0

    • Pave = ½ I0V0

  • Often P is used to represent average power in all AC circuits.


Root mean square rms l.jpg
Root Mean Square (rms)

  • Irms and Vrms are called root mean square current and voltage

  • Found by dividing the max by 2


Convention in usa l.jpg
Convention in USA

  • V0 = 170 V

  • Vrms = 120 V

  • Most electronics specify 120 V, so they really mean Vrms

  • We will always (unless noted) use average power, and root mean square current and voltage

  • Thus all previously learned equations work!


Example l.jpg
Example

  • A 60 W light bulb operates on a peak voltage of 156 V. Find the Vrms, Irms, and resistance of the light bulb.

  • Vrms = 110 V

  • Irms = 0.55 A

  • R = 202 


Example8 l.jpg
Example

  • Why are you not supposed to use extension cords for devices that use a lot of power like electric heaters?

  • P = IV

    • P is large so I is large

  • The wire has some resistance

  • The large current and little resistance can cause heating

  • If wire gets too hot, the plastic insulation melts


Practice problems l.jpg
Practice Problems

  • Don’t write down just answers. Alternatively show your work, too.

  • 611 P 31 – 33, 35

  • Total of 4 measly problems


ad