Rosewill Computer Case 422 Informações Técnicas descarregar pdf (Página 60)

Power Supply Voltages

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Disassembly

and Power

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Tech

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Figure 4.26 Installing an ATX power connector on a motherboard

Another purpose for a power supply is to provide cooling for the computer. The power sup-

ply’s fan circulates air throughout the computer. Most computer cases have air vents on one

side, on both sides, or in the rear of the computer. The ATX-style power supply blows air inside

the case instead of out the back. This is known as reverse flow cooling. The air blows over the

processor and memory to keep them cool. This type of power supply keeps the inside of the

computer cleaner than older styles.

Don’t block air vents

Whether a computer is a desktop model, a tower model, or a desktop model mounted in

a stand on the floor, ensure that nothing blocks the air vents in the computer case. Do not

place a laptop on a blanket or pillow, causing the vents to be blocked.

Electronic components generate a great deal of heat but are designed to withstand fairly

high temperatures. Auxiliary fans can be purchased to help cool the internal components of a

computer. Some cases have an extra mount and cutout for an auxiliary fan. Some auxiliary fans

mount in adapter slots or drive bays.

Be careful when installing an auxiliary fan

Place the fan so the outflow of air moves in the same direction as the flow of air generated

by the power supply. If an auxiliary fan is installed inside a case in the wrong location, the

auxiliary air flow could work against the power supply air flow, reducing the cooling effect.

Figure 2.19 in Chapter 2 details how air flow can be aided with an auxiliary fan.

Power Supply Voltages

Refer to Figure 4.21 and notice how +3.3, +5, –5, +12, and –12 volts are supplied to the moth-

erboard. The motherboard and adapters use +3.3 and +5 volts. The –5 volts is seldom used. If

the motherboard has integrated serial ports, they sometimes use +12V and –12V power. Hard

drives and optical drives commonly use +5 and +12 volts. The +12 voltage is used to operate

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Rosewill Computer Case 422 Informações Técnicas Página 60