Capacitance Equivalent

  • Thread starter cjames9001
  • Start date
  • #1
cjames9001
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Homework Statement


The equivalent capacitance of the capacitors shown in the figure is 9.23 MicroF



Homework Equations



[URL]http://upload.wikimedia.org/math/2/f/5/2f5b978fd081ea63e204909addf3d028.png[/URL]
[URL]http://upload.wikimedia.org/math/f/a/3/fa34ce461e6988fd973081401cc9790c.png[/URL]

The Attempt at a Solution


[URL]http://session.masteringphysics.com/problemAsset/1122585/1/Walker.21.58.jpg[/URL]
So to find C I Attempted to add the Series ones across the top and the left most capacitor with the following calculation:

[1/(1/c+1/12+1/8.35)]=[1/({100.2+20.35c}/100.2c)]=(100.2c)/(100.2+20.35c)

then I took (100.2c)/(100.2+20.35c) and added it to 7.22 microF +4.25 microF =9.23 microF
Then I got :
(100.2c)/(100.2+20.35c)=-2.24

100.2c=-2.24*(100.2+20.35c)

100.2c= -224.448 - 45.584c

145.784c = -224.448

c=-1.540
Which is not correct, and I'm also pretty sure that capacitors can't be negative right?

Homework Statement





Homework Equations





The Attempt at a Solution

 
Last edited by a moderator:

Answers and Replies

  • #2
gneill
Mentor
20,945
2,886
Components are not in series if there are other components attached to the nodes that join them. In the figure, only the 12 and 8.35 microfarad capacitors are in series.
 

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