Download Wiley CompTIA A+ Complete Review Guide: Exam 220-701 / Exam 220-702

Principles of Laptops and Portable Devices 65
Because different hardware is available in docked versus undocked configurations, you
may want to set up hardware profiles in Windows to account for the differences.
Autoswitching and Fixed Input
Autoswitching power supplies allow you to use the same supply for more than one voltage.
Most autoswitching power supplies can operate on voltages from 100 to 240, allowing them
to be used in countries almost anywhere in the world. Fixed-input power supplies, on the
other hand, regulate the voltage coming in to make certain it stays consistent.
Notebook Batteries
When you’re shopping for notebook batteries, be aware not only of the physical size and
shape (which vary depending on the notebook manufacturer’s specifications) but also of the
battery technology:
Nickel-Cadmium (NiCad) The least preferable. Must be recharged every 3 to 4 hours.
A full recharge can take as long as 12 hours. These batteries tend to lose their ability to
hold a charge unless they’re fully discharged each time before being recharged. Leaving
the notebook PC plugged in all the time and using the battery only occasionally for short
periods can eventually ruin the battery.
NiCad batteries are not likely to be on any new device these days.
Nickel-Metal Hydride (NiMH) Better than NiCad because they don’t use heavy metals
with great toxicity. They can also store up to 50 percent more power and don’t suffer loss
of functionality from partial draining and recharging.
Lithium Ion (Li-ion) Lightweight and have a long life, plus they aren’t subject to problems
with partial draining and recharging. They tend to be more expensive than NiCad or NiMH,
however.
Fuel Cell Casio has announced plans to produce a hydrogen fuel cell battery for notebook
computers that promises to last 20 hours or more on a single charge. By the time you read
this, it may be available, offering greatly increased performance but at a much higher price
than normal notebook batteries.
When dealing with batteries, you must be careful not to dispose of them in the normal
way, for they may harm the environment; whenever possible, recycling them is recommended. Here are some rules from the back of a typical battery:
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Don’t put in fire or mutilate; may burst or release toxic materials
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Don’t crush, puncture, incinerate, or short external circuits
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Don’t short-circuit; may cause burns