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The total impedance of a circuit decreases when a capacitor is added in series with L and R. Explain why ? |
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Answer» For an LR circuit, the impedance, ZLR = \(\sqrt{R^2+X_L^2}\), where XL is the reactance of the inductor. ZLCR = \(\sqrt{R^2+(X_L -X_C)^2}\) because in the case of an inductor the current lags behind the voltage by a phase angle of \(\cfrac{\pi}{2}\)rad while in the case of a capacitor the current leads the voltage by a phase angle of \(\cfrac{\pi}{2}\)rad. The decrease in net reactance decreases the total impedance (ZLCR < ZLR). |
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