3. Computer Power Supplies

Question 1

What does the acronym AC denote

Answer 1

Alternating current

Question 2

What does the acronym DC denote

Answer 2

Direct current

Question 3

In which unit is the amount of power output from a power supply measured?

Answer 3

watts

Question 4

What are the typical voltage ouputs by the supply unit in a PC

Answer 4

• +3.3 Volts
• +5 Volts
• +12 Volts

Question 5

In addition to +3.3 volts, +5 volts, + 12.0 volts, which voltages are found on an ATX power supply

Answer 5

-12 volts and -5 volts

Question 6

4-pin molex

Answer 6

A connector that is used to connect pre-SATA floppy and hard disk drives, and provides 12 V of power to many diffent types of peripheral devices

Question 7

6-pin PCIe

Answer 7

A connector that provides an additional 75watts of power to a PCIe Video card

Question 8

Multi-rail PSU

Answer 8

A PSU configuration that provides separate 12V circuits in order to provide extra protection against power spikes on high current circuits

Question 9

Power Supply Unit (PSU)

Answer 9

It converts AC power from the wall into the right kind of power for the individual parts of your computer

Question 10

PSU wattage calculator

Answer 10

A calculator that allows one to enter the system’s components and calculate suggested power supply output

Question 11

Single-rail PSU

Answer 11

A PSU configuration in which all computer components share the PSU’s single 12V circuit, drawing what they need, when they need it from a single source

Question 12

Items needed to replace a DC power jack in a laptop

Answer 12

• a soldering iron
• rosin core solder
• desoldering pump
• isopropyl alcohol
• toothbrush

Question 13

Steps to replace a DC power jack in a laptop

Answer 13

1. Power down and unplug the computer
2. remove the battery
3. disassemble the laptop and remove the motherboard
4. desolder the contacts securing the DC jack to the motherboard
5. Gently pull the DC jack pings from the power jack terminals on the motherboard
6. Clean the power jack terminals on the motherboard with the isopropyl alcohol and toothbrush
7. apply a fresh coat of solder to the power jack terminals on both sides of the motherboard
8. apply a fresh coat of solder to the new power jack’s pin
9. slide the power jack pins into the power jack terminals on the motherboard
10. solder all power jack contacts
11. assemble the device by performing all disassembly steps in reverse order