
12 Phasors
12.1
Introduction
Chapter 11 showed that problems in a.c. circuits can be solved using
phasors. A phasor has both magnitude and direction and it can be
resolved into two components at right angles to each other. Figure
12.1 shows a phasor OA, and this can be written as
x + }y
O x
Figure
12.1
x is the horizontal component, and the operator / is introduced to
indicate that the other component is along the y axis.
x + jy is called a complex number, x, the horizontal component, is a
real number. If the vertical component is an imaginary number,
Figure 12.1 shows that the length of the phasor OA is
V(*
2
+ y
2
) (modulus)
and the phase angl ...