(以下圖文內容皆取材自 Belden 技術文章)
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___1. The most common conductor material used in
electronic cable is:
A.
Copper
B. Copper covered
steel
C.
Aluminum
D. Copper
alloy
___2. The conductivity of copper is:
A.
18%
B.
45%
C. Approximately
85%
D.
100%
___3. The most common type of stranding used in electronic
wire & cable products is:
A.
Bunch
B. Rope
Lay
C.
Unilay
D.
Unistrand
___4. Most Belden conductors are tinned
because:
A. It helps prevent
oxidation.
B. It reduces conductor cost
by 15%.
C. It makes crimp
termination easier.
D. It makes the conductor
more suited to high frequency applications.
___5. Conductors can be made more flexible
by:
A. Using a thinner
insulation.
B. Increasing the number of
strands.
C. Silver
coating.
D. Lengthening the length of
lay.
___6. The most common conductor for fixed applications
is:
A.
Solid
B. 7
strand
C. 10
strand
D. 16
strand
___7. Copper covered steel
conductors:
A. Are stronger than
copper.
B. Have better conductivity
than copper at RF.
C. Are not used in
Broadband/CATV cables.
D. Are used only in non-NEC
cables.
___8. The advantages of a stranded over a solid
conductor:
A. Longer flex
life.
B. Less
costly.
C. Less
flexibility.
D. Improved
strength.
___9. MATCH (2
points)
Flex Life
________
Stranding
________
Lay
________
Flexibility
________
Skin Effect
________
A. The ease with
which a conductor can be bent.
B. As the frequency increases, the
flow of electrons is limited to the surface of the conductor.
C. A measure of the
ability of the conductor to bend repeatedly without breaking.
D. Twisting a group
of wires to form a single conductor.
E. The distance
required for one strand to complete one revolution about the strand which it is
cabled.
__10. The primary purpose(s) of the shield
is/are:
A. To contain
electrical energy.
B. Protection from
external interference.
C. Color
coding.
D. Both A and
B.
___11. The shield material chosen is determined
by:
A. Required shield
effectiveness.
B. Mechanical
strength.
C.
Cost
D. All of the
above.
___12. The advantages of the Beldfoil shield
are:
A. Low frequency
shield effectiveness.
B. Tensile
strength.
C. Physical
strength.
D. 100%
coverage.
___13. Belden’s shorting fold:
A. Eliminates the
escape of energy through the slot.
B. Is isolated from
the drain wire.
C. Degrades shield
performance.
D. Eliminates metal
to metal contact.
___14. The Duofoil shield:
A. Has an extra
layer of polyester.
B. Improves shield
reliability and effectiveness.
C. Reduces flex
life.
D. Is more effective
at low frequencies.
___15. Braid shields:
A. Can be copper or
aluminum.
B. Provide marginal
flex life.
C. Are effective at
high frequencies.
D. Provide 100%
coverage.
___16. Braid shields, when compared to foil shields,
are:
A. Lighter
weight.
B. Easier to
terminate.
C. Stronger,
mechanically.
D. Lower
cost.
___17. MATCH (2
points)
Drain Wire
_________
Shield
_________
Braid
_________
Crosstalk
_________
Beldfoil
_________
A. Contains
electrical energy.
B. Mylar and
aluminum.
C. Eases
termination.
D. Transfer of
energy from one cable member to another.
E. One set of
strands is applied clockwise, the other counter clockwise.
___18. Thermoplastic materials:
A. Include PVC,
Polyethylene, and FEP.
B. Will not melt at
high temperatures.
C. Are most popular
in cable constructions.
D. Both A and
C.
E. All of the
above.
___19. Thermoset materials have advantages that
include:
A. Easier to color
than thermoplastic materials.
B. Will melt at high
temperatures.
C. Excellent low
temperature characteristics.
D. Tend to kink and
curl.
E. Both A and
C.
___20.
The primary purpose of the jacket is:
A. Protection from
the environment.
B. To isolate the
conductors, electrically and physically, within a cable.
C. Protection from
external interference.
D. Protection from
crosstalk.
___21. Polyethylene:
A. Excellent
moisture resistance.
B. Very good
dielectric properties.
C. Used in direct
burial.
D. All of the
above.
___22.
PVC:
A. Rarely used for
cable insulations.
B. Poor flame and
water resistance.
C. Has a variety of
formulations.
D. Is difficult to
color.
___23.
Polyurethane is:
A. Used in highly
abrasive environments.
B. A thermoset
material.
C. Very flame
retardant.
D. Used as coaxial
cable insulation material.
___24.
FEP has many outstanding advantages including:
A. Low flame
spread.
B. Low
cost.
C. High
elongation.
D. All
of above.
___25.
Dielectric strength is:
A. The determining factor
for capacitance, impedance, and relative performance.
B. The material’s ability to
withstand voltage breakdown.
C. The maximum voltage
allowed by UL to be applied.
D. The physical breaking
strength of the insulation material.
___26.
Neoprene:
A. Similar to rubber
characteristics.
B. Good oil and ozone
resistance.
C. Has good aging
characteristics.
D. All of the
above.
___27.
Lower dielectric constant means:
A. Low
attenuation.
B. Low
capacitance.
C. High velocity of
propagation.
D. All of the above.
___28.
Solid insulation is:
A. Most
common.
B. Has air
voids.
C. Difficult to
apply.
D. Used to reduce the
dielectric constant.
___29.
Cellular or foamed insulations are:
A. Most
common.
B. Have no air
voids.
C. Easy to
apply.
D. Used to reduce the
dielectric constant.
___30.
MATCH ( 2 points)
Temperature rating
_________
Velocity of propagation
_________
Capacitance
_________
Tensile strength
_________
Attenuation
_________
Elongation
_________
Dielectric strength
_________
- A. A measure, expressed in picofarads per foot, of the material’s ability to store electrical energy.
- B. A measure, expressed in decibels per 100 feet, of the cable’s loss of electrical energy.
- C. The insulation’s ability to contain or withstand voltage without breaking down.
- D. The range of temperatures at which a material can be used without degradation.
- E. How far an insulation will stretch before it breaks.
- F. The amount of force, measured in pounds per square inch, that it takes to break an insulation.
- G. Expressed as a percentage, the transmission speed of an electrical signal down a length of a cable compared to its speed in free air, which is also the speed of light.
A
D C A B
A
A A C-D-E-A-B D
D
D A B A
C
C-A-E-D-B D C A
D
C A A B
D
D A D
D-G-A-F-B-E-C
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