RC Series Circuit

A circuit that contains pure resistance R ohms connected in series with a pure capacitor of capacitance C farads is known as RC Series Circuit.

Let ,

V=rms value of applied voltage

I=rms value of the circuit current

Voltage across R ,VR=IR where VR is in phase with I.

voltage across C,Vc=IXc where Vc lags I by 90°.

Taking current as references phasor .

The voltage drop VR=IR is in phase with current and is represented in magnitude and direction by the phasor OA.The voltage drop Vc=IXc lags behind the current by 90° and is represented in magnitude and direction by the phasor AB.

The applied voltage V is the phasor sum of these two drops

I. Phase angle

Current I leads the applied voltage V by Φ°.

since current is taken as reference phasor, negative phase angle implies that voltage lags behind the current. This is the same thing as current leads the voltage.