Chapter 21: Zener Diodes
MULTIPLE CHOICE
1. When a reverse-biased voltage is applied that is high enough to cause breakdown in a zener diode, a
high ____ flows.
a.
maximum zener current
c.
zener test current
b.
reverse current
d.
zener current
2. The ____ of a zener diode is determined by the resistivity of the diode. This, in turn, is controlled by
the doping technique used during manufacturing.
a.
breakdown voltage
c.
derating factor
b.
power dissipation rating
d.
reverse voltage
3. The breakdown voltage is typically rated with 1% to ____ tolerance.
a.
10%
c.
30%
b.
20%
d.
40%
4. A ____ is given by the diode manufacturer to determine the power rating at different temperatures
from the ones specified in their tables.
a.
voltage-temperature coefficient
c.
power dissipation rating
b.
breakdown voltage
d.
derating factor
5. High-power zener diodes are stud mounted with a(n) ____ case.
a.
epoxy
c.
metal
b.
glass
d.
tungsten
6. The reverse voltage is approximately ____ of the zener voltage (EZ).
a.
20%
c.
60%
b.
40%
d.
80%
7. Zener diodes that have a breakdown voltage of ____ V or more have a positive zener voltage-
temperature coefficient, which means that the breakdown voltage increases as the temperature
increases.
a.
two
c.
four
b.
three
d.
five
8. Zener diodes with a breakdown voltage between four and five volts may have a ____ voltage-
temperature coefficient.
a.
negative
c.
positive
b.
positive or negative
d.
zero
9. Zener diodes that have a breakdown voltage of less than ____ V have a negative zener voltage-
temperature coefficient, which means that the breakdown voltage decreases with an increase in
temperature.
a.
four
c.
six
b.
five
d.
seven
10. A zener diode can be used to stabilize or regulate voltage. For example, it can be used to compensate
for power-line voltage changes or load-resistance changes while maintaining a constant ____.
a.
breakdown voltage
c.
zener current
b.
DC output
d.
reverse voltage
COMPLETION
1. The applied reverse voltage at which the breakdown occurs is called the ____________________.
2. The ability of a zener diode to dissipate power decreases as the temperature ____________________.
3. The ____________________ is the maximum reverse current that can flow in a zener diode without
exceeding the power dissipation rating specified by the manufacturer.
SHORT ANSWER
1. Describe how a temperature-compensated zener diode is formed.
2. Describe the proper setup and conduct of a zener diode regulation test.