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

The 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 the 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

**Phase angle **

Current I leads the applied voltage V by Φ°.

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