The power supply converts (ps) household current from 115 voltage to four DC
voltages. They are +12, -12, +5, and -5 volts. Now you ask your self why DC and
those voltages? (We don't want to talk about the amperage........headache?)
Because the devices and components of a computer work on DC current. It is
cheaper to make a DC device than a AC device, DC devices create less heat. DC
motors are more efficient than AC motors (there are motors in fans, hard drives,
floppy drives, tape drives, and CD ROM drives).
So lets talk about the ps First and Foremost
DO NOT open up a
power
supply! A defective one is even more dangerous. The ps is made up of
capacitors, diodes, resistors, transistors (yes they are still around) and
coils.
The main reason I say do not open a ps is the capacitors, capacitors
retain power (voltage with amperage) that is their function. A good capacitor
can retain the designed capacity for long period of time, depending on the
composition and quality of the capacitor it can be years. It does not take very
much current to kill you. (incase you are interested: voltage + amperage =
current, where voltage is amount, amperage is the pressure, current is the flow)
Modern power supplies are sealed so you don't have to worry about getting
shocked if you change one out.
Lets look at a power supply from your point of view:
You go to turn on your computer - nada.
So you go down the checklist of probable causes:
House power on? check
Power at the receptacle? check (the lamp next to the computer is on right?)
Unplugged and plug in the power cable to both the receptacle and the
computer? Check
Hummmm, no power.
How do you know if the power supply is bad?
You don't unless you have another computer to swap it out
to test it.
So be on the safe side and consider it as defective and replace it.
A modern power supply will last the life time of the computer, my main system
has the original power supply, it is over 10 years old.
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ask your question here and we will endeavor to get you the most up to date
answer possible!
current. It is
cheaper to make a DC device than a AC device, DC devices create less heat. DC
motors are more efficient than AC motors (there are motors in fans, hard drives,
floppy drives, tape drives, and CD ROM drives).
