voltages, step-down voltages, or both.
Disregarding the inherent
losses in transformer action, the following rules apply:
Figure 1-13.
Transformers.
(1) If the number of windings in the primary and secondary is
the same, the voltage and the current in the secondary will be the
same as in the primary.
Figure 1-13A illustrates a 1:1 ratio
transformer.
(2) If the number of windings in the primary is greater than in
the secondary, the voltage will be less in the secondary and the
current will be greater. For example, if the number of windings in
the primary is twice that of the secondary, the voltage in the
secondary would be half that of the primary, and the current would be
double that of the primary. Such a transformer is referred to as a
step-down transformer. Figure 1-13B shows the symbol for a step-down
transformer.
(3) If the number of windings in the primary is less than in
the secondary, the voltage in the secondary is greater than in the
primary, and the current will be less. For example, if the number of
windings in the secondary are three times that of the primary, the
voltage in the secondary will be three times that of the primary, and
the current will be one-third. Such a transformer is referred to as
a step-up transformer.
Figure 1-13C shows the symbol for a step-up
transformer.
Transformers have many configurations to meet the needs of the
circuits they supply. Just as with inductors, transformers may have
an air core, a fixed iron core, or an adjustable iron core.
The
output may be varied by adjusting the primary, the secondary, or the
core. The secondary may be tapped to provide a variety of outputs in
the secondary, or the transformer may have more than one secondary to
provide separate outputs (see
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