Notebook systems are designed to use as little power as possible. Common ways notebook systems save power are:
- Turning off any drives that aren't currently being used
- Stepping down the bus speed in the CPU
- Turning off the monitor after a period of inactivity
- Putting the computer to sleep or turning it off automatically
When your laptop is plugged into the wall, it is receiving power through an adapter that converts the AC power from the outlet to DC power usable by the computer. Most adapters can be used on both 110 and 220 AC volt power sources. The energy received through the adapter is divided between running the notebook system and charging the battery.
Remember that most adapters are not interchangeable between laptops because laptops require varying amounts of voltage and amperage and also have different plugs. Before connecting a laptop to an adapter, look at the information listed on the adapter to make sure that it supplies the correct amount of voltage and amperage necessary for your specific laptop and has a plug that will fit properly. Failing to use the correct adapter can cause a laptop to:
- Receive insufficient power to turn on.
- Receive insufficient power to charge the battery.
- Receive an excess of power that will fry the system.
When a laptop is not plugged into the wall, it receives its power from the battery. Batteries wear out over time so you should expect to replace your battery every few years. It is best to never let a battery run extremely low because the life of a battery significantly decreases if it loses all of its charge. The following table lists the battery types that might be used in portable devices:
|Nickel Cadmium (Ni-Cad)||
|Nickel Metal Hydride (NiMH)||
|Lithium Ion (Li-Ion)||
Batteries contain dangerous and regulated chemicals. Always dispose of batteries according to the manufacturer's directions. Disposing of batteries improperly might also be illegal.