COMP TIA A+ Power Supplies

Question 1

What is an Ampere

Answer 1

base unit of current measuring rate of flow per second

Question 2

what is Voltage?

Answer 2

the measure of work required to push an electric charge between two points

Question 3

differentiate between 115v and 220v

Answer 3

Voltage variations are regionally based.

Canada/ US has 110-120 @ 60 Hz

Euro has 220-230 @ 50 Hz

Question 4

differentiate between 5.5v vs 12v

Answer 4

12V Output: powers more demanding components such as GPU/ CPU/ Fans/ Drives
12v rails
has ATX 12V standard

5V output:
24 pin connector
powers integrated circuits, older cpus logic devices.
5v rails, and 5v SB

Question 5

24pin MB adaptor

Answer 5

ATX 24 Pin: Uniquely shaped pins one direction plug in

provides more pwr then old 20 pin connectors

8-Ground pins (Black)
4- +3.3 VDC (orange)
5 +5 VDC (red)
1 +5 VDC standby (purp)
1 -5VDC Yellow
2 +12 VDC Yellow 
1 -12 VDC Blue
One power supply on green
One power supply good (grey)

Question 6

deciding on Wattage Rating values what needs to be determined?

Answer 6

watts = volts * amps

Peak Output Rating - stable pwr supply to components

max wattage output - don’t exceed the max of the power supply

Primary voltage rails - +3.3 +5 and +12 Vs

Question 7

12V Rails are crucial…why?

Answer 7

the components that draw 12V’s are critical the the operation of the PC

need sufficient pwr to the 12V rails
usually multiple 12v’s due to multiple components

total amps of all rails must not exceed total output of the power supply

Question 8

guidelines for power sizing, what are some?

Answer 8

Preventing overload

rule of thumb is 50% excess capacity

Question 9

Differentiate between AC and DC

Answer 9

AC: alternating current
delivered to our homes from the powerline

DC: Direct current
same voltage all the time however doesn’t travel long distances well.

Question 10

Determine the max power output

Answer 10

look at the AC input voltage first
is it adaptable?

read the output guage on the back top down.