Apple Macintosh PowerBook 150 - Manual (Page 76)

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Power Management
Power sources
Your computer can draw its operating power from two different sources:
m
Main battery Your computer’s main power source is a nickel-cadmium
battery. Depending on the battery conservation features you choose, the
battery provides power for about 3 hours of work time.
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AC power You can run your computer from any standard electrical outlet by
plugging in the power adapter.
Your computer also has a backup battery that maintains the contents of RAM
while you replace the main battery. The backup battery does not provide
enough power to run the computer.
These power sources are described in more detail in the following sections.
Responding to low-power messages
When the battery runs low, the computer displays a series of low-power
messages. The work time remaining after you see the first message varies
depending on how you are using the computer. It’s a good idea to act
promptly.
Read this chapter to learn
how you can maximize your
PowerBook battery life.