Do I need a computer AC voltage of 220 volts?

Do I need a computer AC voltage of 220 volts? One of the ironies of the PC lies in the fact that for normal work he needs constant current, and the input power supply unit (PSU) supplied AC 220V. This is understandable: where do we take the direct current - only the usual AC power, bringing it to the desired condition.
Therefore, all the work to transform the current "falls on the fragile shoulders of BP.

What is he, a modern power supply?
Average power of today's BP is 300 to 500W.
BP produces the following voltage:
• Substantive stabilized voltage 5V (current 10-50A);
• 12V (current 3.5-15A) - to supply the engine, and interface circuits;
•-12V (current strength 0.3-1A) - to supply front-end circuits;
•-5V (current 0,3-0,5 A) - not commonly used, is left for compatibility with standard ISA Bus);
• 3,3 V - for food storage.

ATX power supply circuits are standardized color-coded.
Color-coded main connector PSU:
• GND - black ("land");
• 5V - red;
• 12V - yellow;
•-5V - white;
•-12V - blue;
• 3,3 V - orange;
• 3,3 V Sense - brown (serves as a feedback signal voltage 3,3 V);
• 5VSB - Raspberry ("duty" chain Standby);
• PS-ON - green (chain control signal, including the main sources of stress 5, 3,3, 12, -12 and-5V);
• PW-OK - gray (the signal chain of the normal power supply - Power OK).

Color-coded additional connectors:
• 3,3 V Sense - white with brown stripes;
• FanC - white with blue stripes (the signal chain for fan speed control - feeding voltage 0 ... 12 V at a current up to 20mA)
• FanM - white (signal from the sensor tachometric fan BP - two pulses for each revolution of the rotor);
• 1394V - white with red stripes (isolated from the circuit "ground" source voltage 8-48V to power devices bus IEEE-1394 [FireWire])
• 1394R - white with black stripes (- isolated from the circuit "ground" source voltage 8-48V to power devices bus IEEE-1394 [FireWire]).

In modern standard ATX PSU 220V is present only inside the PSU. At the same time inside the system unit, there is only a low voltage direct current (this is done in terms of security).
PSU fan is powered from the network 12B.
Interface power management software allows you to power off (from the operating system - through the Start button, etc.).

 [b] How to test the BP 1,111,115.
Sometimes the PC repair is necessary to verify that the BP. How to do it without connecting to a PC PSU?
To do this, connect the power supply to some load (eg, CD-ROM or floppy drive), to short the green and any black wire in the connector BP (eg, using the paper clip) and turn on the PSU. At the proper BP immediately start working and fan turns on the LED drive (connected as a load).