Power Sources

Portable computers typically have two power sources:

  • AC power

  • Battery power

Battery power is a vital feature for portable computers, which are frequently used away from an AC power source. Battery life depends on several factors, including

  • Battery type

  • Recharging practices

  • Power-management options

  • Memory size

  • CPU speed and type

  • PC Card type and use

Portable computers actually have at least two batteries:

  • Main battery (used to power the computer)

  • CMOS battery (used to maintain CMOS/BIOS settings)

Some also have a third battery called a RAM or bridge battery. This is used for reserve power or to support suspend/restore functions. In this chapter, ...

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