In the given circuit, C1=2μF,C2=0.2μF,C3=2μF,C4=4μF, C5=2μF,C6=2μF, the charge stored on capacitor C4 is ____μC.
Answer: 4
Solution
With the 10V source across the two outer corners, label the four internal junction potentials and apply charge conservation at each junction using Q=CΔV for every capacitor. Solving the node equations for the top-middle, top-right, bottom-middle and bottom-right junctions gives potentials of 7.5V, 5.5V, 2.5V and 4.5V respectively, with the source plates held at 10V and 0V. Capacitor C4 bridges the top-right and bottom-right junctions, so the potential difference across it is 5.5−4.5=1V. The stored charge is Q4=C4ΔV=4μF×1V=4μC. The charge stored on C4 is 4μC.