Electric Circuit Analysis

6.10 Power and Energy in Periodic Waveforms

We locate point B on normalised v

1

(t) first. We are free to locate the similarly located point on

normalised v

2

(t) on either side of B within a span of 2p radians or 360°. This gives us two choices –

point C and point D on the second waveform. If we choose point C, we can conclude that v

2

(t) leads

v

1

(t) by 315°. If we choose point D, we conclude that v

2

(t) lags v

1

(t) by 45°. Therefore, a lag angle

of q radians and a lead angle of (2p-q ) radians mean the same. As a convention, we favour the

angle that turns out to be less than 180°

(or p radians). Thus, in Fig. 6.2-8, we will term ...