# Calculate Equivalent Capacitance

Discussion in 'Electronics Homework Help' started by siva.469, Mar 2, 2012.

1. ### siva.469

1
0
Mar 2, 2012
Hi,

I would like to know the solution for the question attached in the attachement.Can anyone help me please.

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2. ### Harald KappModeratorModerator

9,543
1,969
Nov 17, 2011
Start by simplyfying the circuit:
the two lower left 1F capacitors can be replaced by asingel cap. As can the 1F and 3F cap. in the top middle.

Harald

3. ### Laplace

1,252
184
Apr 4, 2010
You can never go wrong by writing the node equations, but first simplify the circuit by combining parallel capacitors. In the attached drawing I have added a voltage source (V) from which to calculate the current (I). This will be the constraint equation V/I=Zc that the input terminals to the network show a capacitor impedance of 5 farads. So once the equations are done, I let MathCAD crank out the answer. Of course, the final answer has been redacted in accordance with the rules of the forum.

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4. ### john monks

693
1
Mar 9, 2012
What I did was convert all the capacitance into Xc's so that I could convert a Y network into a delta networks and treat them exactly like resistors and convert them back. Then I combined the capacitors except for the 3F and the C and subtracted the number from 5F and got 2.625F. Then I tried took the 3F and C series and tried the answers until I god 2.625F. The result was 21F. There are many ways of looking at this circuit.You can treat the circuit as an AC circuit and do nodal analysis, or thevenize, or do mesh currents, and more. The important thing is to remember exactly what a capacitor is and how it works. The rest is just numbers.  