Electrical Engineering ⇒ Topic : R-L Series A.C. Circuit

R-L Series A.C. Circuit

Fig. (a) shows an R-L series circuit and its phasor diagram. Since the circuit current is taken as the reference phasor (i.e. along OX-axis), we have,

                                                                  I = I + j 0

This shows that applied voltage leads the current by Φ. This is the same thing as the current lags the voltage by Φ.

In practice, we are given the applied voltage and circuit impedance and it is desired to find the circuit current. It is then profitable to take voltage as the reference phasor (i.e., along OX-axis).

Note that phase angle of current is conjugate of impedance angle

Fig. (a) shows the phasor diaarnm of the circuit with voltage as the reference phasor.

                                  figure (a)