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Jake asked in Science & MathematicsPhysics · 8 years ago

What is the effective capacitance of this circuit?

http://img542.imageshack.us/img542/5743/1jxl.jpg

1.) What is the effective capacitance of this circuit? Answer in units of μF.

2.) What is the total energy stored by the 27 μF capacitor on the right-hand side of the circuit? Answer in units of mJ.

If someone could help me out with these two part I'd really appreciate it!

2 Answers

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  • CwCc
    Lv 7
    8 years ago
    Favorite Answer

    Capacitors in parallel add. 26+27 = 53 μF on each side of the circuit. Capacitors in series combine like resistors in parallel. Two equal capacitors in series will have an equivalent capacitance of half. 53/2 = 26.5 μF is the capacitance of the circuit.

    Only half the voltage drop will occur over the parallel combination on the right. The energy stored in a capacitor is given by

    1/2 CV^2 = 1/2 (27 μF)(32 V)^2 = 13.8 mJ

  • 8 years ago

    C1 = 26 μF , C2 = 27 μF , C3 = 26 μF , C4 = 27 μF

    C1 and C2 are connected in parallel and C3 and C4

    are connected in parallel.

    Left hand combination and the Right hand combination

    are in series.

    Left hand side : Cx = C1 + C2 = (26 + 27) μF = 53 μF

    Similarly, Right hand side :

    Cy = C3 + C4 = (26 + 27) μF = 53 μF

    1/ Ceff = 1/Cx + 1/Cy = 2/53

    => Ceff = 53/2 μF = 26.5 μF

    Vx = Vy = 64/2 = 32 V

    Energy stored in the C4 = 27 μF capacitor

    = E = (1/2)C4 (Vy)² = (1/2)(27)(32)² μJ

    = 13824 μJ = 13.824 mJ

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