Chapter 8 Power Supply

Historical/Conceptual

Understanding Electricity

Measured in Volts (V)

The amount of electrons moving past one point is called current or amperage or amps

the amount of amps and volts that the computer needs is called Wattage (Watts or W)

All wires have resistance to flow of electrons

Volume Flowing = amperes (A)

Work = wattage (w)

Pressure = voltage (V)

Resistance = ohms (Ω)

Computer's Electricity

direct current (dc)

alternating current (ac)

Powering The PC

Supplying AC

IEC-220

110 V

120 V

(Most power supplies come in dual-voltage)

901 ( Supplying DC)

902 (Protecting the computer from spikes and sags in AC power

Multimeter (used to check the number of electronics current)

surge suppresor

absorbs the extra voltage from a surge to protect the computer

Joule

power conditioning

Your power line that takes in all kinds of strange signals

Unit of electrical energy (How much energy a surge suppressor can handle before it fails it described in joules

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UPS

protects your computer and your data in case of a power sag or power outage

P1 power connector ( 20 or 24 pin connector)

Molex connector ( supplies 5v, 12v current for fans and older drivers.

Mini connector (that supplies 5v and 12v to peripherals

SATA power connector ( drives need a special 15-pin)

ATX

The bios or operating system takes over from the handles the chore of turning off the PC on or off. It's called soft power.

The ATX12V 1.3. This introduce a 4-pin motherboard power connector unofficially but commonly called P4 power connector.

EPS12 introduced a number of power features that eventually became part of ATX12V. The most important was called rails.

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