Chapter 18: Transformers
MULTIPLE CHOICE
1. When a transformer is operated without a load there is no ____ current flow.
a.
primary
c.
tertiary
b.
secondary
d.
quaternary
2. The primary windings act like a(n) ____.
a.
inductor
c.
capacitor
b.
resistor
d.
generator
3. A transformer with secondary voltage greater than its primary voltage is called a(n) ____.
a.
step-up transformer
c.
isolation transformer
b.
step-down transformer
d.
autotransformer
4. The turns ratio of a(n) ____ is always greater than one.
a.
autotransformer
c.
isolation transformer
b.
step-down transformer
d.
step-up transformer
5. A transformer that produces a secondary voltage less than its primary voltage is called a(n) ____.
a.
isolation transformer
c.
step-down transformer
b.
step-up transformer
d.
autotransformer
6. In a(n) ____ the turns ratio is always less than one.
a.
step-down transformer
c.
isolation transformer
b.
step-up transformer
d.
autotransformer
7. When a transformer steps up the voltage, it steps down the ____ so the output power remains the same.
a.
resistance
c.
capacitance
b.
current
d.
inductance
8. A(n) ____ is a device used to step up or step down applied voltage.
a.
isolation transformer
c.
step-down transformer
b.
step-up transformer
d.
autotransformer
9. A(n) ____ does not step up or step down the voltage.
a.
isolation transformer
c.
step-down transformer
b.
step-up transformer
d.
autotransformer
10. A(n) ____ prevents electrical shock by isolating the equipment from ground
a.
isolation transformer
c.
step-down transformer
b.
step-up transformer
d.
autotransformer
COMPLETION
1. In a transformer, the coil containing the AC voltage is referred to as the ____________________.
2. The ____________________ is a number from 0 to 1, with 1 indicating that all the primary flux lines
cut the secondary windings and 0 indicating that none of the primary flux lines cut the windings.
3. The amount the voltage is stepped down is determined by the ____________________.
SHORT ANSWER
1. Why are transformers rated in volt-amperes (VA) rather than in power (watts)?
2. Describe what transpires in a transformer with a loaded secondary.