<P> Angle notation can easily determine leading and lagging current: </P> <P> A ∠ θ . (\ displaystyle A \ angle \ theta .) </P> <P> In this equation, the value of theta is the important factor for leading and lagging current . As mentioned in the introduction above, leading or lagging current represents a time shift between the current and voltage sine curves, which is represented by the angle by which the curve is ahead or behind of where it would be initially . For example, if θ is zero, the curve will have amplitude zero at time zero . Using complex numbers is a way to simplify analyzing certain components in RLC circuits . For example, it is very easy to convert these between polar and rectangular coordinates . Starting from the polar notation, ∠ θ (\ displaystyle \ angle \ theta) can represent either the vector (cos ⁡ θ, sin ⁡ θ) (\ displaystyle (\ cos \ theta, \ sin \ theta) \,) or the rectangular notation cos ⁡ θ + j sin ⁡ θ = e j θ, (\ displaystyle \ cos \ theta + j \ sin \ theta = e ^ (j \ theta), \,) both of which have magnitudes of 1 . </P> <P> A ∠ θ = A ∠ δ − β (\ displaystyle A \ angle \ theta = A \ angle \ delta - \ beta) </P>

Does the source voltage lag or lead the current