The power supply is the conduit through which this is brought to the computer.

In some countries the voltage supplied is 120 Volts single phase 60 cycles

as in the USA or 50 cycles as In Britain. In some the voltage is 220 Volts double phase.That voltage switch on the supply will indicate which voltage the supply is set for. Using a screwdriver, you can set this switch to the required voltage.

So what does the Power supply do. It takes the house current and breaks it down to the required voltages that the computer use. The Computer use very small amounts of current, known as DC current. The Home use AC current. I will explain both in a nutshell.

AC current is Alternating Current and can kill you, (That is why you MUST stay out of the power Supply). It is used for heavier uses around the home. DC current is Direct Current and can ALSO kill you. (If used with the right combination of parts). It is the type of current found in batteries of different voltages. A standard battery is 1.5 volts of DC current. A torch light use 3 or 4.5 or 6 volts DC current. The telephones in the home uses 50 volts of DC current. The computer uses Varying voltages. +12 volts, +5 volts, +3.3 volts. DC current. So the power supply takes the incoming AC current and breaks it down to different DC voltages for use by the computer. What ever you do, DO NOT OPEN THE COMPUTER POWER SUPPLY.

The power of the power supply is measured in watts. How much watts should the supply have?. You ask. well ,each part use a certain amount of watts of power which can total any where from 250 watts to 350 or higher.

The standard is that the total watts of the power supply must not come near or exceed the total demand of the system. Therefore a wattage of 450 to 750 watt power supply will be adequate.