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:
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).
