L7. Resonant RLC Shift

LC & RLC CIRCUITS - Resonance

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A series RLC circuit is driven by a sine wave generator. The applied voltage and the current through the curcuit are displayed simultaneously on an oscilloscope. At resonance, both voltage and current are in phase. When the driving frequency is changed, however, a phase shift results. At frequencies above resonance, the current lags behind the voltage; below resonance, the current leads.