3.7 Summarize power supply types and features.

Question 1

The power supply provides ___ power voltages for use inside of your computer.

Answer 1

DC

Question 2

Power supplies convert __ power to the __ power that computer components run on.

Answer 2

AC

DC

Question 3

What is the significance of 115V vs. 220V input?

Answer 3

115V is used in North America, 220V is used abroad. Some power supplies may only support one or the other or have a switch to configure compatability.

Question 4

What is the significance of 5V vs. 12V output?

Answer 4

They are the maximum power provided by the power supply connectors inside a PC to individual components.

Question 5

This is the power available at a wall outlet.

Answer 5

AC (alternating current)

Question 6

24-pin motherboard power adapter is keyed, what does this mean?

Answer 6

The connector is keyed so that it can only plug in one way, ensuring that the proper voltages are supplied to the right pins.

Specific pins are designated to supply 5V, 12V, or 3.3V.

Question 7

___ is the total capacity of the power supply.

Answer 7

Wattage rating

Question 8

What kind of current is output in wall outlets outside of North America?

Answer 8

220V AC

Question 9

This must be high enough to meet the total power demands of all components in the computer.

Answer 9

Wattage rating

Question 10

This must be high enough to meet the total power demands of all components in the computer.

Answer 10

Wattage rating

Question 11

What may determine what wattage rating is needed for the power supply?

Answer 11

Number of components

Types of components

Question 12

What may determine what wattage rating is needed for the power supply?

Answer 12

Number of components/device

Types of components/device

Question 13

The type of case the computer is in also needs to be considered to ensure that the power supply…

Answer 13

physically fits properly, has long enough cables.

Question 14

How do you determine the exact wattage requirement you need from your power supply?

Answer 14

Add all of the wattage ratings of the individual components.

Your power supply’s wattage must meet or preferably exceed that total value.

Question 15

The connectors needed are determined by the connector types used on the devices to be powered. For example, if you have an older ATX motherboard, it has a 20-pin ____ connector, while newer models contain the 24-pin ___ connector thanks to the addition of the PCIe bus.

Answer 15

Molex

Question 16

You should always disconnect from any power source when you’re working on any kind of device. You must also remember that some devices will store charge in ___. This charge could provide an electric shock, so you want to be sure that you are discharging any ___ before you begin working on that device.

Answer 16

capacitors

Question 17

Your computer or your laptop uses DC power, direct current, to be able to operate. But the power that’s coming out of your wall outlet is alternating current, or AC. We use power supplies to convert 115 volts AC or 220 volts of AC, depending on where you live in the world, into something your computer can use. Most often, that’s __ volts of DC power, __ volts of DC power, and ___ volts of DC power.

Answer 17

3.3
5
12

Question 18

What is the fundamental difference between alternating currents and direct currents?

Answer 18

Alternating current is constantly reversing direction as it flows through the electrical lines. This allows us to efficiently distribute AC power over very long distances.

The primary characteristic of direct current is that it’s moving in a single direction with a constant voltage. This is what is required by most electronics.

Question 19

If you connect a 220 volt power supply to a 115 volt power source, there is usually no permanent damage.

True or False?

Answer 19

True

Question 20

If you connect a 115 volt power supply to a 220 volt power source, there is usually no permanent damage.

True or False?

Answer 20

False

Can destroy power supply and computer components.

Question 21

~

Answer 21

AC

Answer 22

DC

Question 23

What do switches on power supplies do?

Answer 23

Match input voltage (100v-220v) to the needed voltage. Some power supplies can automatically switch.

Question 24

What can you use to see what kind of power supply you may need for an unknown outlet?

Answer 24

A multimeter. It can measure the voltage of the outlet.

Question 25

You can connect a 24 pin connector to a 20 pin motherboard.

True or False?

Answer 25

True

Question 26

What are some components that would use 12v?

Answer 26

fans, PCIe adapters, hard drive motors

Question 27

What are some components that would use 5v?

Answer 27

some motherboard components

Question 28

What are some components that would use 3.3v?

Answer 28

M.2 slots, RAM, some motherboard components

Question 29

What computer component tends to use the most power?

Answer 29

Graphics card/video card

Question 30

What is one reason to have a power supply above capacity?

Answer 30

Scalability; more power in case extra components are added later.