A+ Essentials Study Guide Laptops - Part 3

2.1 Identify the fundamental principles of using laptops and portable devices Part 3

> Communication connections

Bluetooth

Bluetooth wireless technology is a convenient, wire-free, short-range communication between devices. It is a globally available standard that wirelessly connects mobile phones, portable computers, cars, stereo headsets, MP3 players, and more. The low power consumption, small size and low cost of the chipset solution enables Bluetooth technology to be used in the tiniest of devices. The technology combines small-form factor radio, low power, low cost, built-in security, robustness, ease-of-use, and ad hoc networking abilities.

Bluetooth USB Adapter

Bluetooth technology is an ad hoc technology that requires no fixed infrastructure and is simple to install and set up. You do not need wires to get connected. Bluetooth enabled products do not need to install driver software and since Bluetooth technology operates in the 2.4 GHz, (one of the unlicensed industrial, scientific, medical (ISM) radio bands,) there is no cost for the use of Bluetooth technology.

Infrared

Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of microwave radiation. The name means "below red" (from the Latin infra, "below"), red being the color of visible light of longest wavelength.

Cellular WAN

A wide area network (WAN) for data that is typically provided by the cellular carriers. Also called "wireless broadband" or "broadband wireless," wireless WANs (WWANs) use cellular towers to transmit a wireless signal over a range of several miles to a mobile device compared to wireless Wi-Fi LANs (WLANs), which span only a few hundred feet and generally to only stationary devices.

Cellular Modem PC Card ... see PC Cards

Ethernet

> Power and electrical input devices (e.g. auto-switching and fixed-input power supplies, batteries)

Batteries

Most current notebooks use lithium ion and more recently lithium polymer batteries, which have replaced the older nickel metal-hydride technology. Typical battery life for most laptops is two to five hours with light-duty use, but may drop to as little as one hour with intensive use. Batteries gradually deteriorate over time and eventually need to be replaced in one to five years, depending on the charging and discharging pattern.

Nickel-Cadmium (NiCad) batteries were the first type of battery commonly used in laptop computers, and older laptops sometimes still use them.

• Have a life of approximately two hours between charges.
• Battery life decreases with each charge based on the 'memory effect'. (Gas bubbles form in the cell plates, reducing the total amount of available cell space for recharge). Only way around this is to discharge the battery completely before recharging it.
• If the battery charges too long, it can explode.

Nickel-Metal Hydride (NiMH) batteries are the bridge between NiCad and the newer Lithium-Ion (LiIon) batteries.

• Last longer between charges than NiCad but overall have a shorter total lifespan.
• Suffer from the 'memory effect', but to a lesser extent than NiCad batteries.

Li-Ion batteries (Lithium-ion) The current standard for laptop computers.

• Are light, one of the best energy-to-weight ratios
• Have long life spans, Can last for anything from about 950 up to 1200 charges.
• Do not suffer from the 'memory effect', can be charged randomly, and won't overheat if overcharged.
• Are thinner than any other battery available for laptops, making them ideal for the new ultra-thin notebooks.

lithium polymer batteries (Li-poly) are rechargeable batteries which have technologically evolved from lithium ion batteries. There are many advantages of this design over the classic lithium ion design, including the fact that the solid polymer electrolyte is not flammable (unlike the organic solvent that the Li-Ion cell uses).

Li-poly batteries are also gaining ground in PDAs and laptop computers, such as Apple's MacBook and small digital music devices such as iPods and other MP3 players, as well as portable gaming devices like the Sony PSP or Nintendo's Game Boy Advance SP, where small form factors and energy density outweigh cost considerations.