Name _______________________ Date __________
Circle Your Class Section 21 22 23
CST 1511 WORKSHEET 7
Power Supplies
Directions:
You may use any reference to answer the following questions. Please staple sheets together.
1. The majority of desktop computers use the ______ form factor.
a. SFX
b. EFS
c. LPX
d. ATX
2. Most computer power supplies use a/an __________ power supply.
a. switching
b. constant current
c. variable voltage
d. AC output
3. The primary function of a power supply is to
a. convert VDC to VAC
b. convert digital signals to analog
c. convert VAC to VDC
d. convert analog to digital signals
4. Two voltages not used in modern motherboards are
a. +5 and +12
b. +3.3 and +5
c. -5 and -12
d. +12 and -5
5. The combination of both +12v and -12v were often used for
a. CPU
b. serial port voltages
c. power good signal
d. microprocessor regulators
6. Form factor refers to the supplies
a. output waveform
b. shape and size
c. type of loading required
d. constant output voltage
7. Identify the obsolete form factor
a. ATX
b. TFX
c. LPX
d. EPS
Page 2 – Worksheet 7
Name _______________________
8. Voltage on the RED wire of a power connector indicates ___ volts dc.
a. +12
b. +5
c. +3.3
d. -12
9. What is the function of pin 16 on pin 24 motherboard connector (ATX supply)?
a. ground circuit
b. power switch
c. logic circuitry voltage
d. CPU regulator voltage
10. Newer power supplies contain live voltages inside the power supply when the line cord is plugged in, even if the
computer’s power switch is turned off.
a. TRUE
b. FALSE
11. The power supply is turned on when the PS_ON signal is a logic level “0”.
a. TRUE
b. FALSE
12. The ATX auxiliary power connector is used to
a. supply operating power to the CPU
b. supply power to the peripheral equipment
c. supply power to the fans
d. supply power to a floppy drive
13. The advantage of a 24 pin motherboard connector compared to a 20 pin is that
a. a higher current can be delivered to the board
b. a higher voltage can be delivered to other points on the motherboard
c. there is a savings in the consumed power
d. there is no advantage
14. A +5 vdc path on a circuit board is drawing 2 amperes. The power dissipated in watts is
a. 10
b. 0.4
c. 5.0
d. 3.0
15. The company that introduced a nonstandard ATX design is
a. Compaq
b. HP
c. Dell
d. Gateway
Page 3 - Worksheet 7
Name _______________________
16. What voltage appears on pin 1 of a standard peripheral power connector?
a. +3.3
b. +5.0
c. +12
d. -5.0
17. When testing a power supply outside the computer, the output connectors should all be disconnected from other
devices to make the supply work properly.
a. TRUE
b. FALSE
18. The typical MTBF of a power supply is around _______ hours or better.
a. 100,000
b. 10,000
c. 1,000
d. 100
19. The average power usage of a hard drive is in the range of
a. 50-75 watts
b. 10-25 watts
c. 15-30 watts
d. 25-150 watts
20. What is the maximum number of amperes that can be drawn from a +5 vdc PCI bus
a. 10
b. 5
c. 4.8
d. 0.5
21. ACPI is a type of
a. power management
b. power supply
c. form factor
d. voltage controller
22. The largest contributor to component failure in power supplies is
a. varying input voltages
b. overvoltage
c. humidity
d. temperature
23. Backup power for computers can be supplied by a/an
a. ATM
b. ATX
c. UPS
d. ACPI