Consider a series LCR circuit connected to an AC source
v = vmsinωt ---- (1)
Let i = imsin(ωt + ϕ) ---- (2)
be the instantaneous current through the circuit and ϕ is the phase difference between the applied voltage and the current. Voltage equation at any instant
Its magnitude of v is the phasor sum of vR, vL and vC.
And the phasor diagram for the circuit is as shown below. The symbols in the diagram are having usual meaning.
is analogous to resistance in DC called impedance, Z.
