VOLTAGE AND TURNS RATIO
The input winding to a transformer is called the primary
winding. The output winding is called the secondary
winding. If there are more turns of wire on the primary
than on the secondary, the output voltage will be
lower than the input voltage. This is illustrated in Figure
14-8 for a step-down and a step-up transfonner. Notice
that the winding with the greater number of turns has the
higher voltage. In Figure 14-8, one winding has twice as
many turns as the other. In one case the voltage is
stepped down to half, while in the other the voltage is.
stepped up to double.
It is important to know the ratio of the number of
turns of wire on the primary winding as compared to the
secondary winding. This is called the turns ratio of the
transformer, Equation 14.1. The actual number of turns
is not important, just the turns ratio.