
Related Terms
RLC Series Circuit
The RLC Series Circuit is defined as when a pure resistance of R ohms, a pure inductance of L Henry and a pure capacitance of C farads are connected together in series combination with each other. As all the three elements are connected in series so, the current flowing in each element of the circuit will be same as the total current I flowing in the circuit.

In the RLC Series Circuit
XL = 2πfL and XC = 1/2πfC
When the AC voltage is applied through the RLC Series Circuit the resulting current I flows through the circuit, and thus the voltage across each element will be
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VR = IR that is the voltage across the resistance R and is in phase with the current I.
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VL = IXL that is the voltage across the inductance L and it leads the current I by an angle of 90 degrees.
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VC = IXC that is the voltage across the capacitor C and it lags the current I by an angle of 90 degrees.
Phasor Diagram of RLC Series Circuit

The phasor diagram of the RLC Series Circuit when the circuit is acting as an inductive circuit that means (VL>VC) is shown below and if (VL< VC) the circuit will behave as a capacitive circuit.
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Steps to draw the Phasor Diagram of the RLC Series Circuit
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Take current I as the reference as shown in the figure above
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The voltage across the inductor L that is VL is drawn leads the current I by a 90-degree angle.
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The voltage across the capacitor c that is Vc is drawn lagging the current I by a 90 degree angle because in capacitive load the current leads the voltage by an angle of 90 degrees.
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The two vector VL and VC are opposite to each other.
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The three cases of RLC Series Circuit
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When XL > XC, the phase angle Ï• is positive. The circuit behaves as a RL series circuit in which the current lags behind the applied voltage and the power factor is lagging.
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When XL < XC, the phase angle Ï• is negative, and the circuit acts as a series RC circuit in which the current leads the voltage by 90 degrees.
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When XL = XC, the phase angle Ï• is zero, as a result, the circuit behaves like a purely resistive circuit. In this type of circuit, the current and voltage are in phase with each other. The value of power factor is unity.