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Capacitors do not play an important role in DC circuits because it
is impossible for a steady current to flow across a capacitor. If an
capacitor is connected across the terminals of a battery of voltage
then a transient current flows as the capacitor plates charge up.
However, the current stops flowing as soon as the charge on the positive plate
reaches the value . At this point, the electric field between the
plates cancels the effect of the electric field generated by the battery,
and there is no further movement of charge. Thus, if a capacitor is
placed in a DC circuit then, as soon as its plates have charged up, the capacitor
effectively behaves like a break in the circuit.