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| AC Circuit with Pure Capacitance only |
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| Let an AC source be connected across pure inductive element. |
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| If E = Eosinwt then, |
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| q = EC = CEo sin wt |
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| I = Io cos wt |
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| Here Io = Eo Cw = EoCw |
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 plays the role of a resistance and
is known as capacitive reactance Xc. |
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| Therefore the non-resistive of a coil to a.c. due to the varying magnetic field is called capacitive reactance Xc. |
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| Unit of Xc is also Ohm |
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| The current leads the EMF by 90o and the phasor diagram is: |
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| For DC, Xc becomes infinite and hence, capacitance block DC flowing through it. |
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