3.5 Given a scenario, install or replace the appropriate power supply Flashcards
Meaning of PSU?
Power Supply Unit
What do PSUs do?
Supply low-voltage DC power to PC components
DC = Direct Current
Why do PSUs contain a rectifier?
To convert AC power to DC power
(AC = Alternating Current) (DC = Direct Current)
2 factors that determines the power supply’s compatiblity?
- Size
- Power connectors
Most PSUs designed for use with desktop PCs are based on the ATX form factor
What voltage is typically used in North America?
120 VAC
What voltage is typically used in the United Kingdom?
230 VAC
What does it mean that most PSUs are dual voltage & auto-switching?
They can adapt to different input voltages automatically
Some PSUs feature a manual voltage switch; fixed types suit either low-line or high-line voltages. Clear voltage compatibility indication is crucial in PSUs and their documentation.
What is the range of low-line VAC?
This would be used in regions like North America
100-127 VAC
What is the range of high-line VAC?
This would be used in regions like teh United Kingdom
220-240 VAC
What is power measured in?
Watts
How is Watts calculated?
Voltage multiplied by current (V*I)
What power output does a PSU need to power a PC?
Combined power requirements of the PC’s components
What is the PSU’s output capability measured in?
Wattage rating
What PSU rating is used for standard desktops?
200-300W
What PSU rating is used for workstations & servers?
Over 300W
Due to meeting the demands of multiple CPUs, additional memory modules, disk drives, & tape units. Gaming PCs might require 500W or better power supplies to cope with the high specification CPU & graphics card(s)
What does PSU efficiency refer to?
The measure of converting grid power to usable PC Power
The higher the percentage the better
If a PSU operates at 75% efficiency, it draws more power from the outlet than its output. The extra energy is lost as heat. With rising energy costs and environmental concerns, selecting an efficient PSU is crucial. ENERGY STAR 80 PLUS compliant PSUs must maintain 80% efficiency across load levels.
3 voltages that PSUs supply to components?
- 3.3V
- 5
- 12V
Not all components use power at precisely these voltages. Voltage regulators are used to correct the voltage supplied form the PSU to the voltage required by the component.
How is a modular PSU unique to other PSUs?
Has detachable power connector cables
What systems mainly use redundant power supplies?
Servers
What is required to use redundant power supplies?
Compatible motherboard
