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Electronics
From Wikipedia, the free encyclopedia

The field of electronics is the study and use of systems that operate by controlling the flow of electrons (or other charge carriers) in devices such as thermionic valves and semiconductors. The design and construction of electronic circuits to solve practical problems is part of the field of electronics engineering, and includes the hardware design side of computer engineering.
The study of new semiconductor devices and their technology is sometimes considered as a branch of physics. This page focuses on engineering aspects of electronics.

Content
1 Overview of electronic systems and circuits
2 Electronic devices and components
3 Analog circuits
4 Digital circuits
5 Mixed-signal circuits
6 Heat dissipation and thermal management
7 Noise
8 Electronics theory
9 Electronic test equipment
10 Computer aided design (CAD)
11 Construction methods
12 Branch page

Overview of electronic systems and circuits
Commercial digital voltmeter checking a prototypeElectronic systems are used to perform a wide variety of tasks. The main uses of electronic circuits are the controlling, processing and distribution of information, and the conversion and distribution of electric power. Both of these uses involve the creation or detection of electromagnetic fields and electric currents. While electrical energy had been used for some time to transmit data over telegraphs and telephones, the development of electronics truly began in earnest with the advent of radio. One way of looking at an electronic system is to divide it into the following parts:
Inputs – Electronic or mechanical sensors (or transducers), which take signals from outside sources such as antennae or networks, (or signals which represent values of temperature, pressure, etc.) from the physical world and convert them into current/voltage or digital signals.
Signal processing circuits – These consist of electronic components connected together to manipulate, interpret and transform the signals. Recently, complex processing has been accomplished with the use of Digital Signal Processors.
Outputs – Actuators or other devices such as transducers that transform current/voltage signals back into useful physical form.
One example is a television set. Its input is a broadcast signal received by an antenna or fed in through a cable. Signal processing circuits inside the television extract the brightness, colour and sound information from this signal. The output devices are a cathode ray tube that converts electronic signals into a visible image on a screen and magnet driven audio speakers.

Electronic devices and components
Main article: Electronic component
An electronic component is any indivisible electronic building block packaged in a discrete form with two or more connecting leads or metallic pads. Components are intended to be connected together, usually by soldering to a printed circuit board, to create an electronic circuit with a particular function (for example an amplifier, radio receiver, or oscillator). Components may be packaged singly (resistor, capacitor, transistor, diode etc.) or in more or less complex groups as integrated circuits (operational amplifier, resistor array, logic gate etc). Active components are sometimes called devices rather than components.

Analog circuits
Main article: analog circuits
Hitachi J100 adjustable frequency drive chassis.Most analog electronic appliances, such as radio receivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a continuous range of voltage as opposed to discrete levels as in digital circuits. The number of different analog circuits so far devised is huge., especially because a 'circuit' can be defined as anything from a single component, to systems containing thousands of components.
Analogue circuits are sometimes called linear circuits although many non linear effects are used in analoge circuits such as mixers, modulators etc. Good examples of analog circuits are valve or transistor amplifiers, operational amplifiers and oscillators.
Some analog circuitry these days may use digital or even microprocessor techniques to improve upon the basic performance of the circuit. This type of circuits is usually called 'mixed signal'.
Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non linear operation. An example is the comparator that takes in a continuous range of voltage but puts out only one of two levels as in a digital circuit. Similarly, a transistor amplifier overdriven can take on the characteristics of a controlled switch having substantially only two levels of output.

Digital circuits
Main article: digital circuits
Digital circuits are electric circuits based on a number of discrete voltage levels. Digital circuits are the most common mechanical representation of Boolean algebra and are the basis of all digital computers. To most engineers, the terms "digital circuit", "digital system" and "logic" are interchangeable in the context of digital circuits. In most cases the number of different states of a node is two, represented by two voltage levels labeled "Low" and "High". Often "Low" will be near zero volts and "High" will be at a higher level depending on the supply voltage in use.
Computers, electronic clocks, and programmable logic controllers (used to control industrial processes) are constructed of digital circuits. Digital Signal Processors are another example.
Building-blocks:
logic gates
flip-flops
counters
registers
multiplexers
Schmitt triggers
Highly integrated devices:
microprocessors
microcontrollers
Digital signal processor (DSP)
Field Programmable Gate Array (FPGA)

Mixed-signal circuits
Main article: Mixed-signal circuit
Mixed-signal circuits refers to integrated circuits (ICs) which have both analog circuits and digital circuits combined on a single semiconductor die or on the same circuit board. Mixed-signal circuits are becoming increasingly common. Mixed circuits contain both analog and digital components. Analog to digital converters and digital to analog converters are the primary examples. Other examples are transmission gates and buffers.

Heat dissipation and thermal management
Main article: Thermal management of electronic devices and systems
Heat generated by electronic circuitry must be dissipated to prevent immediate failure and improve long term reliability. Techniques for heat dissipation can include heatsinks and fans for air cooling, and other forms of computer cooling such as liquid cooling for computers. These techniques use convection, conduction, & radiation of heat energy.

Noise
Main article: electronic noise
Associated with all electronic circuits is noise. Noise is generally defined as any unwanted signal that is not present at the input of the circuit. Noise is not the same as distortion caused by the circuit.

Electronics theory
Main article: Mathematical methods in electronics
Mathematical methods are integral to the study of electronics. To become proficient in electronics it is also necessary to become proficient in the mathematics of circuit analysis.
Circuit analysis is the study of methods to solve linear systems for the unknown variables such as the voltage at a certain node or the current though a certain branch of a network. A common representation of this is the SPICE circuit simulator.
Also important to electronics is the study and understanding of electromagnetic field theory.

Electronic test equipment
Main article: Electronic test equipment
Electronic test equipment is used to create stimulus signals and capture responses from electronic Devices Under Test (DUTs). In this way, the proper operation of the DUT can be proven or faults in the device can be traced and repaired.
Practical electronics engineering and assembly requires the use of many different kinds of electronic test equipment ranging from the very simple and inexpensive (such as a test light consisting of just a light bulb and a test lead) to extremely complex and sophisticated such as Automatic Test Equipment.

Computer aided design (CAD)
Main article: Electronic design automation
Today's electronics engineers have the ability to design circuits using premanufactured building blocks such as power supplies, resistors, capacitors, semiconductors (such as transistors), and integrated circuits. Electronic design automation software programs include schematic capture programs such as ORCAD, used to make circuit diagrams and printed circuit board layouts.
Construction methods
Many different methods of connecting components have been used over the years starting with point to point wiring using tag boards attached to chassis, through printed circuit boards and ending with highly integrated circuits. Some of the methods previously used are:
Point-to-point construction
Cordwood construction
Wire wrap
Printed circuit boards

Branch pages
Digital electronics
Analogue electronics
Microelectronics
Fuzzy electronics
Electronic Devices and Circuits
Integrated circuit
Optoelectronics
Printed circuit board
Semiconductor
Semiconductor device

For more information on Electronics, please visit
Wikipedia.
Gadget
From Wikipedia, the free encyclopedia

An Apple iPod, a popular gadgetA gadget or gazza is a device that has a useful specific purpose and function. Gadgets tend to be more unusual or cleverly designed than normal technology. In some circles the distinction between a gadget and a gizmo is that a gizmo has moving parts, whereas a gadget need not have them. For example, a nifty digital watch would be a gadget, while an analog watch would be a gizmo.
In contrast, a device of clever design that has no practical purpose is called a novelty item.
The etymology of the word gadget is disputed. Some sources say it was "invented" when Gaget, Gauthier & Cie, the company behind the casting of the Statue of Liberty, made a small-scale version of the monument and named it after their firm. Other sources cite a derivation from sailors' terminology; the French gâchette which has been applied to various pieces of a firing mechanism; the French gagée, a small tool or accessory; the French engager, to engage one thing with another; or even a diminutive of the Scottish engineering jargon gadge, a form of measuring device. The spring-clip used to hold the base of a vessel during glass-making is also known as a gadget.
The first atomic bomb was nicknamed the gadget by the scientists of the Manhattan Project, tested at the Trinity site.
In fiction, gadgets are best known in popular spy films, especially in the James Bond series (See List of James Bond gadgets). Superheroes, especially ones like Batman and Iron Man whose premise revolves around equipment, have numerous gadgets themselves. There is a cartoon character, Inspector Gadget, whose super powers come from an assortment of gadgets. Also, one of the main characters of the Disney cartoon show Chip 'n Dale Rescue Rangers, Gadget Hackwrench, possess an innate ability to create tools and other technology out of trash and junk.

Examples of gadgets
mp3 players
Can opener
Electric Toothbrush
Mini Vac
Blender
The Clapper
Swiss Army Knife
Remote control device of any sort (car starter, TV, garage door opener, etc.)
Cordless mouse
Sonic screwdriver
Any device that talks, like a calculator or clock
Tools

For more information on Gadgets, please visit
Wikipedia.
Camera
From Wikipedia, the free encyclopedia

This is the article about the photographing device. For other uses, see CAMERA.
A camera is a device used to take pictures (usually photographs), either singly or in sequence, with or without sound recording, such as with video cameras. A camera that takes pictures singly is sometimes called a photo camera to distinguish it from a video camera. The name is derived from camera obscura, Latin for "dark chamber", an early mechanism for projecting images in which an entire room functioned much as the internal workings of a modern photographic camera, except there was no way at this time to record the image short of manually tracing it. Cameras may work with the visual spectrum or other portions of the electromagnetic spectrum.

Contents
1 Description
2 History
3 Camera brands

Description
Every camera consists of some kind of enclosed chamber, with an opening or aperture at one end for light to enter, and a recording or viewing surface for capturing the light at the other end. Most cameras have a lens positioned in front of the camera's opening to gather the incoming light and to focus the image, or part of the image, on the recording surface. The diameter of the aperture is often controlled by a diaphragm mechanism, but some cameras have a fixed-size aperture.

The size of the aperture and the brightness of the scene control the amount of light that enters the camera during a period of time, and the shutter controls the length of time that the light hits the recording surface. For example, in lower light situations, the shutter speed should be slower (longer time spent open) to allow the film to capture what little light is present.
There are various ways of focusing a camera accurately. The simplest cameras have fixed focus and use a small aperture and wide-angle lens to ensure that everything within a certain range of distance from the lens (usually around 3 metres (10 feet) to infinity) is in reasonable focus. This is usually the kind found on one-use cameras and other cheap cameras. The camera can also have a limited focusing range or scale-focus that is indicated on the camera body. The user will guess or calculate the distance to the subject and adjust the focus accordingly. On some cameras this is indicated by symbols (head-and-shoulders; two people standing upright; one tree; mountains).
Rangefinder cameras focus by means of a coupled parallax unit on top of the camera. Single-lens reflex cameras allow the photographer to determine the focus and composition visually using the objective lens and a moving mirror to project the image onto a ground glass or plastic micro-prism screen. Twin-lens reflex cameras use an objective lens and a focusing lens unit (usually identical to the objective lens) in a parallel body for composition and focusing. View cameras use a ground glass screen which is removed and replaced by either a photographic plate or a reusable holder containing sheet film before exposure.
Traditional cameras capture light onto photographic film or photographic plate. Video and digital cameras use electronics, usually a charge coupled device (CCD) or sometimes a CMOS sensor to capture images which can be transferred or stored in tape or computer memory inside the camera for later playback or processing.
Cameras that capture many images in sequence are known as movie cameras or as ciné cameras in Europe; those designed for single images are still cameras. However these categories overlap, as still cameras are often used to capture moving images in special effects work and modern digital cameras are often able to trivially switch between still and motion recording modes. A video camera is a category of movie camera which captures images electronically (either using analogue or digital technology).
Stereo camera can take photographs that appear "three-dimensional" by taking two different photographs which are combined to create the illusion of depth in the composite image. Stereo cameras for making 3D prints or slides have two lenses side by side. Stereo cameras for making lenticular prints have 3, 4, 5, or even more lenses.
Some film cameras feature date imprinting devices that can print a date on the negative itself.

History
Main article: History of the camera
Camera obscura
19th century studio camera, with bellows for focusing.The first permanent photograph was made in 1826 by Joseph Nicéphore Niépce using a sliding wooden box camera made by Charles and Vincent Chevalier in Paris. However, while this was the birth of photography, the camera itself can be traced back much further. Before the invention of photography, there was no way to preserve the images produced by these cameras apart from manually tracing them.
The first camera that was small and portable enough to be practical for photography was built by Johann Zahn in 1685, though it would be almost 150 years before technology caught up to the point where this was possible. Early photographic cameras were essentially similar to Zahn's model, though usually with the addition of sliding boxes for focusing. Before each exposure a sensitized plate would be inserted in front of the viewing screen to record the image. Jacques Daguerre's popular daguerreotype process utilized copper plates, while the calotype process invented by William Fox Talbot recorded images on paper.
The development of the collodion wet plate process by Frederick Scott Archer in 1850 cut exposure times dramatically, but required photographers to prepare and develop their glass plates on the spot, usually in a mobile darkroom. Despite their complexity, the wet-plate ambrotype and tintype processes were in widespread use in the latter half of the 19th century. Wet plate cameras were little different from previous designs, though there were some models (such as the sophisticated Dubroni of 1864) where the sensitizing and developing of the plates could be carried out inside the camera itself rather than in a separate darkroom. Other cameras were fitted with multiple lenses for making cartes de visite. It was during the wet plate era that the use of bellows for focusing became widespread.

Camera brands
Voigtländer VitoretAgfa
ARCA-Swiss
Agilux
Balda
Bolex
Braun
Bronica
Burke & James
Cambo
Canon
Casio
Contax
Corfield
Coronet
Ebony
FED
Folmer & Schwing
Fujifilm
Graflex
Hasselblad
Hewlett Packard
Holga
Horseman
Ilford
Imaging Solutions Group (ISG)
Kodak
Konica
Leica
Linhof
Lomo
Minolta
Mamiya
Minox
MPP
Mustek
Newman & Guardia
Nikon
Olympus
Osaka
Panasonic
Pentax
Polaroid
Praktica
Reid
Ricoh
Rollei
Samsung
Sigma Corporation
Sony
Thornton-Pickard
Vivitar
Voigtländer
Wisner
Wray
Yashica
Zeiss
Zenit
Zone VI
Zorki

For more information on Cameras, please visit
Wikipedia.
IPod
From Wikipedia, the free encyclopedia

A white 5th Generation iPod (iPod with Video) with a case and earbuds.The iPod is a brand of portable media players designed and marketed by Apple Computer. Devices in the iPod family provide a simple user interface designed around a central scroll wheel (with the exception of the iPod shuffle). The standard iPod model stores media on a built-in hard drive, while the smaller iPod shuffle and iPod nano use flash memory. Like most digital audio players, an iPod can serve as an external data storage device when connected to a computer.
Discontinued versions of the iPod include two generations of the popular iPod mini and four generations of the full-sized iPod, all of which had monochrome screens except for the fourth-generation iPod with color screen (previously sold as iPod photo before it replaced the monochrome iPod in the main line). As of October 2005, the lineup consists of the 5th generation iPod, which has video playback capabilities, the iPod nano which has a color screen, and the iPod shuffle; all three models were released in 2005.

Contents
1 Name
2 History
3 Design
4 Operation
5 Capabilities
5.1 Software
5.1.1 iTunes Music Store
5.1.2 Additional features
5.2 Hardware
5.2.1 Earphones
5.3 Compatibility
6 Models
6.1 Timeline of iPod models
6.2 iPod
6.2.1 1st generation
6.2.2 2nd generation
6.2.3 3rd generation
6.2.4 4th generation
6.2.4.1 iPod photo/iPod with color display
6.2.4.2 iPod U2 Special Edition
6.2.4.3 Harry Potter Collector's iPod
6.2.5 5th generation
6.2.5.1 Harry Potter Collector's iPod (30 GB)
6.3 iPod mini
6.3.1 1st generation mini
6.3.2 2nd generation mini
6.4 iPod shuffle
6.5 iPod nano
7 Patents and patent disputes
8 Common criticisms
8.1 Battery life
8.2 Non-replaceable batteries
8.3 Bass response
8.4 Equalizer bass distortion
9 Accessories
9.1 iPod A/V cable and alternatives
9.2 iPod Camera Connector
9.3 iPod Hi-Fi
9.4 Car integration and accessories
10 iPod sales
11 Advertising

The iPod is currently the world's best-selling digital audio player. The bundled software used for uploading music, photos, and videos to the iPod is called iTunes. A music jukebox application, iTunes stores a comprehensive library of the user's music on their computer, and can play and rip music from a CD. The most recent incarnations of iPod and iTunes have video playing and organization features.

Apple's widespread marketing campaigns have led to the iPod's reputation as an easy-to-use, stylish device and dominance among the MP3 market (to the extent that some people erroneously refer to all MP3 players as "iPods"); this has led to a large market dedicated specifically to iPod accessories. Apple's proprietary actions regarding iPods and iTunes, however, have led to criticism as well as legal battles.

Name
This article or section does not cite its references or sources.
You can help Wikipedia by introducing appropriate citations.
Apple Computer often refers to the player as iPod, without use of the definite article the. Apple's web site reflects this usage (for example, "iPod incorporates the same touch-sensitive Apple Click Wheel that debuted on iPod mini"), which resembles Apple's use of the words Apple Macintosh. When Apple first introduced the iMac, the "i" stood for Internet, meaning that the iMac shipped with everything needed for a connection. Now, many other Apple products start with a lowercase "i". The "i" also stood for "individual" and "independence" — as well as other words that complemented Apple's "Think Different" Campaign launched in conjunction with the first iMac, but the prefix stuck, as the brand recognition associated with it has positive effects on the sales of Apple products. Recently, some media have started referring to the generation primarily born in the late 1980s, and which in particular has made the iPod popular, as the iGeneration, suggesting that the "i" family of products are having a far-reaching cultural impact.[citation needed]

History
Development of the iPod grew out of Apple’s digital hub strategy, as the company was creating software applications for the growing number of digital devices being snapped up by consumers. While digital cameras, camcorders and organizers had well-established markets, the company found digital music players lacking in quality and Apple decided to develop its own. Apple’s Hardware engineering chief Jon Rubinstein assembled a team of engineers to design and build the first iPod in less than a year, with Tony Fadell and Michael Dhuey as the principal hardware engineers. It was unveiled by CEO Steve Jobs on October 23, 2001 as a Mac-compatible product with a 5 GB hard drive that put "1,000 songs in your pocket."[1]
In 2002, Apple released the 2nd generation iPod in two versions, one for Mac users and one for Windows users. The only difference though was the bundled software; since there was no iTunes for Windows at the time, the Windows iPods came packaged with Musicmatch software. The actual iPods could work with either system (though to work with Windows, they had to use the FAT32 filesystem, Mac iPods could use either the FAT32 or HFS Plus filesystem). In 2003, Apple released 3rd generation iPods which included a single CD that included a Windows version of the iTunes software along with the Mac version. The slightly thinner 4th generation changes included a click wheel replacing 4 less-intuitive buttons. 2005's 5th-generation iPod married audio, photo and video functions, with a color screen on all models. Since October 2004, the iPod has dominated digital music player sales in the United States, with over 90% of the market for hard-drive-based players and over 70% of the market for all types of players. The iPod has sold at a tremendous rate, now past 42 million units since its release. Apple and several industry analysts have suggested that the iPod has encouraged users of non-Apple products to switch to other Apple products, such as to Macintosh computers.
On April 26, 2006, EE Times reported that a Samsung Electronics executive vice president had announced that Samsung had won the contract to provide the media processor for a future model iPod, replacing Apple's previous supplier PortalPlayer.[2] PortalPlayer had announced a week before that their updated processor would not be used in upcoming flash-based iPods.[3]

[edit]
Design

iPod third generation internals. Click photo to view detailed description.This article or section does not cite its references or sources.
You can help Wikipedia by introducing appropriate citations.
Jeff Robbin headed the team which developed both the iPod firmware and the iTunes program at Apple. His team integrated the core firmware from PortalPlayer with the user interface library developed by Pixo. (The founder of Pixo had worked on the Apple Newton, a personal digital assistant formerly produced by Apple.) The Pixo libraries provide the user interface, though the iPod photo has incorporated some visual elements from Mac OS X, such as the animated Aqua style progress bar. More recent iPods, such as the iPod nano and fifth-generation iPod, also incorporate the "brushed-metal" effect, previously used in iTunes before version 5.0, in their stopwatch, screen lock and radio features. Until the release of iPod mini, the user interface of all iPods used "Chicago", the font used on the original Macintosh computer from 1984, designed by Susan Kare. The iPod mini uses the "Espy Sans" font (previously seen in eWorld, the Newton, and Copland), while the color 4th generation iPods (previously known as iPod photo) and 5th generation iPods use Myriad, Apple's current corporate typeface.
The unit's case snaps together, with no screws or adhesive involved (though the 4th generation has some adhesive holding the battery in place). The plastic front of the case has clips which lock under a ridge inside the rim of the metal case back. A servicer can pry the iPod open by carefully inserting a small non-metal screwdriver to pull the metal away from the clips.
iPod contains a small internal speaker which generates the scroll-wheel clicks and alarm clock beep sound, but this internal speaker cannot play music.

Operation
All iPods, except the shuffle, have five buttons. The newer iPods have the buttons integrated into the scroll wheel, to give a minimalist and uncluttered interface. The buttons are:
Menu (this traverses backwards through the menus)
Center (this selects a menu item)
Play / Pause (this doubles as an off switch when held)
Fast Forward / Skip Forward
Fast Reverse / Skip Backwards
A Hold switch also exists on the top of the unit to prevent accidental button presses. Newer iPods automatically pause playback when the headphones are unplugged from the headphone jack. However, playback does not resume when the headphones are re-inserted.
The older iPods with FireWire ports can function as external hard drives without any additional iPod functionality in FireWire Disk Mode. An iPod unable to start due to either a firmware or a hardware problem displays the "sad iPod" image.[4] This is reminiscent of the sad Mac icon of earlier Macintosh computers.

Capabilities

Software

The user interface of a 5th generation iPod, shown playing a songThe iPod can play MP3, WAV, M4A/AAC LC, Protected AAC, AIFF, Audible audiobook and Apple Lossless audio file formats. The fifth-generation iPod can also play .m4v and .mp4 MPEG-4 (namely H.264/MPEG-4 AVC) video file formats. The Microsoft Windows version of iTunes can transcode regular non copy-protected WMA files to an iPod supported format. WMA files with copy protection cannot be played in iTunes or be copied to an iPod. Reviewers have criticized the iPod's inability to play some other formats, in particular the Ogg Vorbis and FLAC formats. MIDI files cannot be played on iPods, but can be converted into a compatible audio file format by choosing the "advanced" menu on iTunes.
Using the Rockbox open source jukebox firmware iPods 4G and above are capable of playing Ogg Vorbis, FLAC, Musepack, Wavpack, Shorten, Midi, WAV, AIFF, AAC and of course MP3
Apple designed the iPod to work with the iTunes media library software, which lets users manage the music libraries on their computers and on their iPods. iTunes can automatically synchronize a user's iPod with specific playlists or with the entire contents of a music library each time an iPod connects to a host computer. Users may also set a rating (out of 5 stars) on any song, and can synchronize that information to an iTunes music library.
iTunes lacks the ability to transfer songs from iPod to computer because of legality issues. However, several third-party programs exist that provide music synchronization facilities similar to iTunes, but also offer the ability to copy music from iPod back to the host computer. Notable examples include vPod and the Ml iPod plugin for Winamp.
iTunes Music Store
Main articles: iTunes, iTunes Music Store
The iTunes Music Store (iTMS) is an online music store run by Apple and accessed via iTunes. It was introduced on 28 April 2003 and sells individual songs relatively easily and cheaply (e.g. 0.99 USD, 0.99 Euro, 0.79 GBP). The iPod is the only portable music player that can play the purchased music, and this exclusiveness has helped the store become the dominant online music service.
The purchased audio files use the AAC format with added encryption. The encryption is based on the controversial FairPlay digital rights management (DRM) system. Up to five authorized computers and an unlimited amount of iPods can play the files. Burning the files onto an audio CD removes the DRM, at a cost of reduced quality when re-compressed from one lossy format to another.

iPods cannot play music files encrypted with other rival DRM technologies, such as Microsoft's protected WMA or RealNetworks' Helix-DRM. RealNetworks claims that Apple is creating problems for itself,[5] by using FairPlay to lock users into using the iTunes Music Store. Steve Jobs has stated that Apple makes very little profit from song sales, but Apple uses the iTMS to promote iPod sales.[6]

Additional features
In addition to playing music and storing files, the iPod has limited PDA functionality. Since January 2003, Mac users have been able to synchronize their contacts and schedules Address Book and iCal to their iPods through iSync. With the 2005 release of iTunes 5.0, Apple integrated contact/schedule syncing into iTunes and added the ability for Windows users to synchronize their contacts and schedules from Microsoft Outlook and Outlook Express. Although Mozilla Calendar and Mozilla Sunbird iCalendar have the same file format used by iCal and the iPod, there is no way to automatically sync schedules among these programs. However the files can be manually dragged and dropped into the correct directory on the iPod.
The limited PDA calendar functions of the iPod are somewhat tainted for users from Newfoundland and parts of Australia. Their time zones are excluded from the iPod's firmware, leaving them unable to properly sync calendar events and alarms to their devices. No workaround (including mentally converting times when reading them) is functionally acceptable due to the combined behaviours of iSync, iCal and the iPod with regards to converting events between time zones. Apple has yielded no commitment to correct this problem as of January, 2006.
iPod can also display notes, and hence host simple games and store restaurant information. However, iPod has limitations as a PDA, since users cannot edit this information on the iPod except through a computer.
Most iPods (the exception is the iPod shuffle) also feature games. All new iPods (except the shuffle) feature:
Brick: a clone of the Breakout arcade game from Atari. (Originally created by Apple cofounder Steve Wozniak.)
Parachute: a game in which the user controls a turret and attempts to shoot down paratroopers and the helicopters which release them. Parachute is similar to the Apple II game Sabotage by Mark Allen.
Solitaire: a simple card game resembling the Klondike solitaire card game.
Music Quiz: an interactive music quiz featuring the user's own songs. The game plays a portion of a random song and prompts the user to identify it from a list of 5 (or of 4 on the iPod mini and nano). A song drops off the list every few seconds. The faster the users choose the right song, the more points they get. Music Quiz became available through a free firmware update for third-generation iPods released in October 2003 and later came standard with the iPod mini and fourth-generation iPods. No record is kept of the score, and there is no limit on the number of songs played; however, the songs repeat after the first 100. Music Quiz requires rapid disk seeking and uses a lot of battery power.
Notes: iPod also has the function to read eBooks through use of the Notes Function. This allows the user to read small text files.

Hardware
Originally iPod connected to a user's computer to update songs and recharge its battery solely through FireWire. It could also be charged by connecting it to a small power adapter which shipped for free with the first several generations. The now standard dock connector was not added until the 3rd generation in April 2003, allowing users the option of using FireWire or USB to make data transfers, although the device could still not be charged by USB and the USB cable was not included. Most PC's don't have FireWire ports so this move effectively opened the Windows market to iPod, although USB only Windows users had to keep their FireWire cables to plug into the wall adapter. The dock connector also made it possible to transfer data, sound, and power back and forth to iPod accesories, which created an explosive market of devices that has been extremely profitable for third parties such as Belkin and Griffin. The resulting myriad of connecting devices is still one of iPod's greatest strengths over its competititors.
The fourth-generation iPod could be charged over USB, and eventually Apple started shipping iPods with USB cables instead of FireWire ones. Many Macs shipped before 2004 had only USB 1.1, which has a transfer speed of 11 Mbit/s, as opposed to FireWire's 400 and USB 2.0's 480. Although none of these actually transfers at these exact rates, USB 1.1 is much slower than the other two, and for some users USB 1.1 may simply be unusable for transferring music collections to fill a 40 GB iPod. Later introductions continued to lessen iPod's reliance on FireWire. iPod Shuffle, released in January 2005, plugs directly into a USB port, without a dock connector and has no Firewire support. The iPod nano, released in September 2005, uses a dock connector that allows a FireWire cable to be plugged in to charge the device, but not to transfer data. With the fifth-generation iPod, Apple dropped all support for data transfer over Firewire to any model iPod. Like the nano, the fifth-generation iPod's dock connector will accept a FireWire cable and can draw power from it, but only the USB connection, not the FireWire one, will support data transfer - a message stating this appears on the iPod screen. This has drawn some criticism from the Mac community, since FireWire has been a standard feature on Apple Macs for many years, while USB 2.0 support was only added in October 2003.
The first three generations of iPod used two ARM 7TDMI-derived CPUs running at 90 MHz, while later models have variable speed chips which run at a peak of 80 MHz to save battery life. The iPods use 1.8 inch (46 mm) ATA hard drives (with a proprietary connector) made by Toshiba. The iPod mini uses one-inch Compact Flash microdrive hard drives made by Hitachi. The iPod has a 32 MiB flash ROM chip which contains a bootloader, a program that tells the device to load the operating system from another medium (in this case, the hard drive). All iPods, except for the 60 GB fifth-generation iPod, have 32 MiB of RAM, a portion of which holds the iPod OS loaded from the firmware and the vast majority of which serves to cache songs loaded from the hard drive. For example, an iPod could spin the hard disk up once and copy about 30 MiB of upcoming songs on a playlist into RAM, thus saving power by not having the drive spin up for each song. (The 60 GB fifth-generation iPod holds 64 MiB of RAM, to further extend battery life.)
iPod was originally introduced with a black and white display but no current model uses one. iPod Photo (an addition to the functionality of the 4th generation iPod released in late 2004) introduced a color screen, while iPod shuffle (released January 2005) has no screen at all. When iPod mini was replaced with iPod nano it received a color screen (and photo capabilty) and starting with the 5th generation all full size iPods have color screens and photo capability.

Earphones
All iPods come with earbud headphones with distinctive white cords and earbuds, a color chosen to match the design of the original iPod. The white cords have become symbolic of the iPod brand, and advertisements for the devices feature them prominently. Despite the fact that new generations of the iPod now appear in black as well as white, the headphones remain white, as do the USB cables, chargers, docks, and remotes.
The distinctive earphones have such good recognition characteristics that it has been suggested that they may be a liability – after a 24% rise in robbery and a 10% increase in grand larceny in the NYC subway system, a spokesperson for the New York City Police Department suggested that iPods might be behind the increases[8].

Compatibility
The original iPod was designed for use with Macintosh computers running Mac OS 9 or Mac OS X but Apple began selling a Windows-compatible iPod on July 17, 2002.[9] Apple released a Windows version of iTunes on October 16, 2003;[10] previously, Windows users needed third-party software such as Musicmatch Jukebox (included with Windows iPods before the release of the Windows version of iTunes), ephPod, or XPlay to manage the music on their iPods.
iPods originally shipped formatted with Apple's native filesystem, HFS Plus and consequently would only work with Apple's Mac OS because Windows does not support HFS Plus. An iPod formatted with HFS Plus is able to serve as a boot disk for a Macintosh computer, allowing one to have a usable, portable operating system installed on their iPod. With the advent of the windows-compatible iPod, Apple switched iPod's default file system to FAT32 because FAT32 is the only file system that can be used natively with both Mac OS and Windows. Fourth-generation and earlier iPods could still be made to boot a Macintosh by reformatting their hard disks with HFS Plus.
The iPodLinux project has successfully ported an ARM version of the Linux kernel to run on iPods. It currently supports first through third generation iPods, and features simple installers for Mac OS X and Windows. The Linux interface is known as "Podzilla". The interface will run on all iPods, however the development team does not support its usage. The iPod uses standard USB and FireWire mass-storage connectivity, and therefore any system with mass-storage support can mount it and use it as an external hard drive. The iPod will also charge from any powered USB or Firewire port, regardless of software support.

Models
Timeline of iPod models
A 1st generation pink iPod mini (left), and a 1st generation iPod (right)Apple currently markets three distinct players bearing the iPod name. Some models come with different capacities (a higher capacity allows the storage of more music) or with different designs. The model range as of April 25, 2006 includes the iPod (30 GB and 60 GB), iPod nano (1 GB, 2 GB, and 4 GB) and iPod shuffle (512 MB and 1 GB).
The iPod minis (4 GB and 6 GB and in various colors) are now discontinued, having been replaced by the iPod nano. The iPod U2 Special Edition was also discontinued. The Harry Potter 20 GB Collector's 4th generation iPod was replaced by the Harry Potter 30 GB Collector's iPod, which is simply a 5th generation iPod with a Harry Potter engraving and the Harry Potter audiobooks pre-loaded.

iPod
While all iPods have roughly the same size and the same capabilities, the design has undergone several revisions since its introduction to the market. Five distinct generations of iPods exist, commonly known as: 1st, 2nd, 3rd, 4th, and 5th generations.
Within any generation of iPods, various models with different sizes of hard drives have come onto the market at different price points. During the 3rd generation, three sizes of iPods were marketed, priced at US $299, $399, and $499. Currently, Apple sells two sizes of iPod: a 30 GB hard drive for $299, and a 60 GB model for $399. Note that Apple currently claims 1 GB of storage will hold 250, 4-minute songs in 128 kbit/s AAC. For the 1st and 2nd generation iPod, Apple claimed 1 GB would hold 200 songs. Encoding songs at higher bitrates will take up more space on the hard drive. One can scale this proportion up; the current 30 GB iPod can hold roughly 7,500 songs, though the Apple website states that "actual formatted capacity may be lower."

1st generation
A 1st generation iPod.First announced on October 23, 2001, the original iPod cost $399 with a 5 GB hard drive.[11] Critics panned the unit's price, but iPod proved an instant hit in the marketplace, quickly overtaking earlier hard drive MP3 players such as the NOMAD Jukebox. Apple announced a 10 GB version ($499) in March 2002.[citation needed]
Apple designed a mechanical scroll wheel and outsourced the implementation and development to Synaptics, a firm which also developed the trackpad for Apple's PowerBooks. The 1st generation iPod featured four buttons (Menu, Play/Pause, Back, and Forward) arranged around the circumference of the scroll wheel, and one Select button in the center.

A 2nd generation iPod.
2nd generation
Introduced on July 17, 2002, at Macworld in 10 GB and 20 GB capacities, the 2nd generation iPod replaced the mechanical scroll wheel of the original with a touch-sensitive, non-mechanical one (also manufactured by Synaptics), termed a "touch wheel." Due to new Toshiba hard drives, the 20 GB iPod slightly exceeded its 1st generation counterpart in thickness and weight, while the 10 GB model was slimmer. The 2nd generation iPod came with a carrying case and wired remote and it was the first generation that was compatible with Windows. In December 2002 Apple released 4 limited-edition, laser-engraved, autographed iPods from Beck, Tony Hawk, Madonna, and No Doubt. They sold for $50 over the normal retail price in each capacity until the 2nd generation iPods were discontinued.[12]

[edit]
3rd generation

The 3rd generation iPod featured the four buttons above the touch wheel with "select" in the center.On April 28, 2003, Apple CEO Steve Jobs introduced an "ultrathin" iPod series. Slightly smaller than their predecessors, they had more distinctively beveled edges. Over the life of the 3rd generation iPod series, Apple produced 10 GB, 15 GB, 20 GB, 30 GB, and 40 GB sizes. These iPods use a 30-pin connector called the Dock Connector — longer and flatter than a FireWire connector. The iPod Dock came bundled with all but the least expensive iPod and also retailed separately.

The 3rd generation iPod featured touch-sensitive buttons located between the display and touch wheel. The new buttons featured red backlighting, allowing easier use in darkness. The touch-sensitive buttons, which build upon the touch-sensitive scroll wheel introduced in the 2nd generation iPod, make the 3rd generation iPod unique in that it has no external moving parts (other than the hold slider on the top of the unit) and is the only iPod that doesn't have its buttons surrounding the wheel. With the 3rd generation iPod, Apple stopped shipping separate Mac and Windows versions of the unit. Instead, all iPods now shipped with their hard drives formatted for Macintosh use; the included CD-ROM featured a Windows utility which could reformat them for use with a Windows PC.
The 4th generation iPod integrated the four buttons into the scrollwheel.[edit]
4th generation
In July 2004, Apple released the 4th generation iPod. In a new publicity route, Steve Jobs announced it by becoming the subject of a Newsweek magazine cover. The 4th generation iPod is considered the model in which sales greatly increased, thus starting the "iPod Craze."
In the most obvious difference from its predecessors, the 4th generation iPod carries over the click-wheel design introduced on the iPod mini. Some users criticized the click wheel because it does not have the backlight that the 3rd generation iPod's buttons had, but others noted that having the buttons on the compass points largely removed any need for backlighting. Apple also claimed that updated software in the new iPod allows it to use the battery more efficiently and increase battery life to 12 hours. Other minor changes included the addition of a "Shuffle Songs" option on the top-level menu to make it more convenient for users. After many requests from users asking for these improvements to operate on earlier iPods as well, Apple on February 23, 2005, released a firmware update which brings the new menu items to 1st-3rd generation iPods.
Originally, the 4th generation iPod had a monochrome screen and no photo capabilities, like its predecessors. It came in one of two sizes: 20 GB for $299 and 40 GB for $399. In February 2005 Apple discontinued the 40 GB model and began solely selling a monochrome 20 GB version. The monochrome 4th generation iPod, slightly thinner (about one millimeter less) than the 3rd generation iPod, introduced the ability to charge the battery over a USB connection.

iPod photo/iPod with color display
An iPod photo with color screenFor more information on iPod photo prior to its merger with the main iPod line, see iPod photo.
Released on October 28, 2004, iPod photo (originally named iPod Photo — with a capital P for "Photo" — but renamed less than a month after its launch)[citation needed] featured a 220 x 176-pixel (maximum pixel count of 38,720), 16-bit color screen capable of displaying 65,536 colors, and the ability to store and display JPEG, BMP, GIF, TIFF, and PNG images. One millimeter thicker than the standard monochrome fourth-generation iPod, iPod photo could also play music for up to 15 hours per battery charge. It originally came in 40 GB and 60 GB versions, which cost $499 and $599, respectively.

On February 23, 2005, Apple discontinued the 40 GB model; and introduced a lower-priced 30 GB model; which included only a USB cable and no dock, and dropped the price of the 60 GB model. However, unlike the first iPod photos, the lower-priced 60 GB and the new 30 GB models lacked the dock, FireWire cable, carrying case, or AV cables.

On June 28, 2005, Apple Computer merged the iPod and iPod photo lines,[13] removing all monochrome models from the main iPod line, giving the 20 GB iPod all of the capabilities of the former iPod photo line for $299, the same price as the previous monochrome version. The price of the 60 GB iPod photo, now known as iPod 60 GB, dropped from $449 to $399, and Apple discontinued the $349 30 GB iPod photo model. Apple Computer — as well as prominent fan sites (such as iLounge) — continued to refer to this lineup as 4th generation iPods.

iPod U2 Special Edition
The color U2 iPodOn October 28, 2004, Apple released a black-and-red edition of the fourth-generation iPod called iPod U2 Special Edition. Originally retailing for $349, it had a black front with a red click wheel (the colors of U2's latest album, How to Dismantle an Atomic Bomb), and featured the signatures of U2's band members engraved on the back. It also included an iTunes Music Store coupon redeemable for $50 off the price of The Complete U2, a "digital boxed set" featuring over 400 tracks of U2 music.[14]
On June 28, 2005, at the same time as the announcement of the merger of the iPod and the iPod photo lines, Apple added a color screen and photo capabilities to the iPod U2 Special Edition while dropping the price to $329. On October 12, 2005, Apple discontinued the iPod U2 Special Edition with the introduction of the 5th generation iPod. The U2 iPod was the last iPod to ship with Firewire connection cables and firmware, prompting some analysts to speculate about the future inclusion of Firewire interfaces on Apple products.

Harry Potter Collector's iPod
On September 7, 2005, Apple released a limited-edition Harry Potter 4th generation 20 GB iPod that featured a laser engraved Hogwarts crest on the back. This model was superseded on October 12, 2005 with a 5th generation Harry Potter 30 GB Collector's iPod. The iPod was launched along with Harry Potter audiobooks on the iTunes Music Store. Included on the collector's edition was the first six books of the Harry Potter series.

5th generation
A 5th generation 30 GB iPod in a dockOn October 12, 2005 Apple launched the 5th generation iPod at the "One more thing..." event.[15] This iPod is often called the iPod video or the video iPod, while Apple documentation refers to it as the Fifth Generation iPod or iPod with video (compare with the Fourth Generation iPod or iPod with color display, the Third Generation iPod or iPod with dock connector, and Second Generation iPod or iPod with touch wheel).[16]

5th generation iPods are available in 30 GB and 60 GB capacity models and are priced the same as the previous generation at $299 and $399 USD, respectively. They also feature the ability to play MPEG-4 and H.264 video with resolutions of up to 480 x 480 (maximum macroblock (16x16 pixel) count of 900) and 320 x 240 (maximum macroblock (16x16 pixel) count of 300), respectively (videos purchased from the iTunes Music Store are limited to 320 x 240). Some users have reported the ability to play widescreen resolutions up to 640x360 using MPEG-4 and 400 x 192 using H.264 (total macroblock count falls within the stated maximums).[17]

5th generation models have a 65,536 color (16-bit) screen,[18] with a 320 x 240 QVGA transflective TFT display, and are able to display video on an external TV via the AV cable accessory, which plugs into the headphone minijack and splits into composite video and audio output connectors with RCA jacks. They can also display video on an external TV using the iPod AV or S-video cables with the iPod Universal Dock. The dimensions are 103.5 x 61.8 x 11.0 mm for the 30 GB version, and 103.5 x 61.8 x 14.0 mm for the 60 GB version. The screen size is now 2.5 inches (6.35 cm) diagonally, 0.5 inches (12.7 mm) larger than the previous iPod. It is also 30% thinner than the previous full-size iPod. The reported battery life for the 30 GB is 14 hours and for the 60 GB is around 20 hours. Watching movies reduces that amount to 2 and 3 hours respectively.


5th generation black 60 GB iPod with standard accessoriesThe click wheel design is the same as the previous generation, but is marginally smaller (1.5" diameter) than before. The new click wheel is completely flat, unlike older models where the center button is slightly rounded and raised. Apple stopped producing iPods with the click wheels used in the 4th generation iPod and iPod mini from their previous supplier, Synaptics, and now use an in-house solution.

Like the iPod nano, the 5th generation iPod comes in two colors, white and black, and it features the World Clock, Stopwatch, and Screen Lock applications. In addition, the earphone plug is smaller. 5th generation iPods also come with a thin slip case, most likely in response to many complaints concerning the iPod nano's easily-scratched surface. Apple also discontinued the inclusion of an AC adapter and FireWire cable. One must purchase these items separately in order to charge the iPod from a household outlet, or use an external, powered USB hub. The 5th generation iPod no longer supports file transfers via FireWire, but still supports charging using FireWire. This is most likely due to the increased popularity of Hi-Speed USB 2.0 in the consumer market as well as decreasing manufacturing component costs by lowering the complexity of the circuit boards and removing unnecessary accessories.


5th generation Harry Potter 30 GB Collector's iPod[edit]
Harry Potter Collector's iPod (30 GB)
On October 12, 2005 Apple reintroduced the Harry Potter collectible iPod along with an update of the iPod line. The new Harry Potter iPod retains the laser-engraved Hogwarts crest on back of the device and is sold with the "complete Harry Potter" (the first 6 books in the Harry Potter series). The capacity of this model iPod was increased to 30 GB from the previous 20 GB. The price remains the same as the fourth-generation model.

iPod mini
Main article: iPod mini
Apple entered the market for "mini"-form-factor digital audio players in January 2004, with the introduction of the iPod mini, competing directly with players like Creative's Zen Micro and Digital Networks Rio Carbon. The iPod mini had largely the same feature set as the full-sized iPod, but lacked support for some third-party accessories. Its smaller display had one fewer line than previous models, limiting the on-screen track identification to title and artist only, and not the album. In addition, it introduced the ability to charge over a USB connection. The iPod minis used Microdrive hard drives for storage. The iPod mini was discontinued on September 7, 2005, after Apple announced it was to be replaced by the iPod nano, which was 62% smaller in size and included a color screen.

1st generation mini
1st generation iPod mini in Dock with Belt ClipOn January 6, 2004, Apple introduced the first iPod mini. It had 4 GB of storage and a price of $249 (at the time, only $50 below the 15 GB 3rd generation iPod). Critics panned it as too expensive, but it proved to be overwhelmingly popular, and Apple Stores had difficulty keeping the model in stock.
The iPod mini introduced the popular "click wheel" that was incorporated into later iPods: the touch-sensitive wheel means that users can move a finger around it to highlight selections on the screen, while the unit's Menu, Back, Forward, and Play/Pause buttons are part of the wheel itself, letting a user press down on part of the wheel to activate one of those functions. The center button still acted as a select button. Apple initially made iPod mini devices available in five colors: silver, gold, blue, pink, and green. Silver models sold best, followed by blue ones, while the least popular model was gold.

2nd generation mini
In February 2005, the 2nd generation[19] iPod mini came on the market with a new 6 GB model at $249 and an updated 4 GB model priced at $199. Most notably, both models featured an increased battery life of up to 18 hours. In addition, they featured richer case colors (though Apple discontinued the gold color) and other minor aesthetic changes (the color of the lettering on the click wheel now matched the color of the iPod mini). Also, the 2nd generation minis did not include the AC adapter or the FireWire cable bundled with previous models.

iPod shuffle
An iPod shuffle with earphones and carrying necklace.Main article: iPod shuffle
Apple announced iPod shuffle at Macworld Expo on January 11, 2005 with the taglines "Life is random" and "Give chance a chance." iPod shuffle introduced flash memory (rather than a hard drive) to iPods for the first time. The shuffle comes in two models: 512 MB (up to 120 four-minute songs encoded at 128 kbit/s) and 1 GB (up to 240). Unlike other iPod models, iPod shuffle cannot play Apple Lossless or AIFF encoded audio files—possibly due to the iPod shuffle's smaller processing power. The shuffle has a SigmaTel processor. One review regards it as having one of the best-sounding audio systems of all the iPod models.[20]

The iPod shuffle has no screen and therefore has limited options for navigating between music tracks: users can play songs either in the order set in iTunes or in a random (shuffled) order. Users can set iTunes to fill iPod shuffle with a random selection from their music library each time the device connects to the computer. The iPod shuffle weighs less than one ounce (0.78 oz. or 22 g), the lightest iPod to date, and approximates in size to a pack of chewing gum. (Originally, the iPod shuffle website contained a footnote advising people not to eat the iPod shuffle like gum; it was later removed, possibly because several users photographed themselves with their iPod shuffles in their mouths.) Like the rest of the iPod family, iPod shuffle can operate as a USB mass storage device. The 512 MB iPod Shuffle is US$69, and the 1 GB model is US$99 (originally US$99 and US$149, 1 GB model later dropped to US$129).

iPod nano
iPod nanoMain article: iPod nano
On September 7, 2005, Apple announced the successor to the iPod mini, the iPod nano. Based on flash memory instead of a hard drive, the iPod nano is 6.9 mm (0.27 inches) thick, weighs 42 g (1.5 ounces), and is 62 % smaller by volume than its predecessor. It's available in both black and white, in 1 GB (introduced on 7 February 2006, at US $149), 2 GB (US $199), and 4 GB (US $249) models. It has a 65 536 color screen that can display photographs. It connects to a computer via USB 2.0, and the headphone jack is located at the bottom. It retains the standard 30-pin dock connector for compatibility with third-party peripherals. The nano was the first dock-connector iPod that could not sync to a computer (Windows or Mac) using a FireWire cable, though it can still be charged via a FireWire cable.

Patents and patent disputes
In 2005, Apple Computer faced two lawsuits claiming patent infringement by the iPod and its associated technologies:[21] Advanced Audio Devices claimed the iPod breached their patent on a "music jukebox,"[22] while Hong Kong-based IP portfolio company Pat-rights filed suit claiming that Apple's FairPlay technology breached a patent[23] issued to inventor Ho Keung Tse. The latter case also includes the online music stores of Sony, Real Networks, Napster and Musicmatch as defendants.[24]
Apple's application to the United States Patent and Trademark Office for a patent on "rotational user inputs,"[25] as used in the iPod's interface, received a third "non-final rejection" (NFR) in August 2005. Also in August 2005, Creative Technology, one of Apple's main rivals in the MP3 player market, announced that it too held a patent[26] on part of the music selection interface used by the iPod, which Creative dubbed the "Zen Patent", granted on August 9, 2005.[27] On May 15, 2006, Creative filed suit against Apple for patent infringement with the United States District Court for the Northern District of California. The company also asked the United States International Trade Commission to investigate whether Apple was breaching U.S. trade laws by importing iPods into the United States.[28]
Common criticisms
Battery life
The current iPod models use internal lithium-ion batteries (the 1st and 2nd generations used lithium polymer batteries). Apple states that the 60 GB and 30 GB iPods have battery lives of “up to 20 hours” and “up to 14 hours” respectively.[29] Many users of the 30 GB video iPod report battery lives of around 7 hours on average.[30] A review of the same iPod by Ars Technica found that its battery lasted for approximately 10 hours, however they note that it had been "improperly charged."[31]
In 2003, class action lawsuits were brought against Apple complaining that the battery charges lasted for shorter lengths of time than stated and that the battery degraded over time.[32] However, this was resolved in a lawsuit and free replacements for all affected iPods were offered.[citation needed] It should be noted that lithium-ion batteries degrade by various amounts during their lifetime. Guidelines are available for maximizing runtime operation[33] and prolonging life-span.
Non-replaceable batteries
The battery in all iPod models cannot be removed or replaced by the user without levering the unit open. This is unusually difficult for a consumer device, although some rival products have a similar enclosed battery. Compounding this problem, Apple initially would not replace worn-out batteries. The official policy was that the customer should buy a refurbished replacement iPod, at a cost almost equivalent to a brand new iPod. This situation led to a small market for third-party battery replacement kits.
Apple announced a battery replacement program on 14 November 2003, a week before[34] a high publicity stunt and website by the Neistat brothers.[35] The initial cost was $99,[36] but has since been lowered to $59. One week later Apple offered an extended iPod warranty for $59.[37] Third party companies offer cheaper battery replacement kits which often use higher capacity batteries. The battery in the most recent iPods cannot be replaced because they are either soldered onto the main board with the nano, or attached to a metal backplate, on the video iPod.[38]
Bass response
The 3rd generation iPod had a weak bass response, as shown in several audio tests.[39][40] The combination of the undersized DC blocking capacitors and the typical low impedance of most consumer headphones, form a low-frequency rejection filter, which attenuates the low-frequency bass output by up to 10 dB. The same undersized capacitors are used in the 4th and 5th generation iPods,[41] but not in the Shuffle. The problem is substantially reduced when using high impedance headphones, such as the Sennheiser HD 600/650.
Equalizer bass distortion
If the sound is enhanced with the iPod’s software equalizer (EQ), many users (since 2002),[42][43][44][45] have noticed that some EQ settings – like R & B, Rock, Acoustic and Bass Booster – can cause bass distortion too easily.
The equalizer amplifies the digital audio level beyond the software's maximum level, causing distortion (or clipping) on songs that have a bass drum or use a bassy instrument, even when the amplifier output level is very low. Notable examples include Bob Sinclar's Love Generation[46] and Jem's Wish I.[47] One possible workaround is to reduce the volume level of the recorded MP3, using audio analysis tools. This can however take several hours with a large music collection, and it doesn't work with DRM-encrypted music. Also, different tools are needed for each different file format.
Accessories
Apple FM Radio remote accessory.The large accessories market that has built up around the iPod is sometimes described as the iPod ecosystem. A host of different companies produce accessories that are designed to work with the iPod. Companies such as JBL, Bose, Altec Lansing, and Kensington all make speakers that are designed specifically to work with the iPod, using the iPod's thirty pin dock connector. Other companies, such as Griffin Technology and Monster Cable, make add-ons that allow the iPod to record sound, recharge "on the go", play music over the radio, or be used wirelessly with a remote.
Besides technological peripherals there are also cases. iPod owners buy these accessories not only to protect their iPods (See Also "Stratches, Protective cases") but also to make fashion statements. Kate Spade, iSkin, Speck, Incase, and Chums all produce these cases. Some are silicone while others are hard plastic. Apple itself makes some cases. Along with the introduction of the nano Apple introduced nano tubes (a pun on nanotubes), a silicone case with no screen, dock connector, or headphone port protection, but a cover over the click wheel and the hold switch. A new and popular alternative to hard cases are thin vinyl "skins" from companies such as GelaSkins or iStyles. Accessories for the iPod have been added to the skiing and snowboarding industry. Burton Snowboards have developed a jacket and a backpack with Softouch. This is a panel on a jacket sleeve or on a backpack strap that allows the user to control his song selection from that panel. It makes use of the iPod in the outdoors much more convenient.
At the Macworld Expo 2006, Steve Jobs introduced a new wired remote control for the 5th Generation iPod and iPod nano. Named "iPod radio remote", it uses an iPod Shuffle-like interface to control these iPods. It also adds radio tuning capability, with station details being displayed on the iPod screen. Support for this accessory was added in iPod firmware 1.1. The remote is connected via the iPod dock connector (as the remote port seen on previous iPods is not included on the 5th generation iPod or iPod nano), and includes a shorter pair of apple headphones to reduce clutter.
iPod A/V cable and alternatives
The headphone connector on the fifth generation iPod (iPod with Video) accepts an Apple-branded A/V cable with RCA connectors for composite video and stereo analog audio. Apple sells this compatible cable for $19 USD. In what is seen as an attempt to force users to purchase the costly cable, (this is actually due to concerns about the iPod's compatibility with all standard 3.5-inch audio jacks) Apple deviates from standard A/V cables by swapping the composite video connector (usually yellow) and right channel audio connector (usually red). Users attempting to connect a conventional mini A/V cable will only see corrupted video and right audio because the equipment will attempt to render the audio stream as video and vice versa.
iPod Camera Connector
The iPod Camera Connector allows the transfer of digital photo files from a digital camera, or media card reader, to a color screen iPod (4G Photo and 5G Video) using a small adapter attached to the dock connector.

iPod Hi-Fi
Main article: iPod Hi-Fi
An iPod Hi-Fi with its box and with its speaker grill removed and an Apple Remote beside it.At Apple's "Fun Products" Day (February 28, 2006), Steve Jobs announced the iPod Hi-Fi for immediate sale at the price of $349.[48] The iPod Hi-Fi is an amplified loudspeaker system that docks with the iPod. The dimensions of the Hi-Fi are 17" x 6.6" x 6.9". The unit can either be plugged into the wall or run on six D-cell batteries. The Hi-Fi weighs slightly under 17 pounds. Integrated carrying handles allow for easier transportation of the Hi-Fi. The Hi-Fi utilizes two 80-mm wide-range cones and one 130-mm woofer cone.

Car integration and accessories
BMW released the first iPod automobile interface to come from an automotive company.[49] The interface allowed drivers of late-model BMW vehicles to control their iPod through the built-in steering wheel controls and the radio head unit buttons. The iPod attached to a cable harness in the car's glove compartment and allowed the driver to create up to five unique "BMW playlists" that were displayed through the vehicle's radio head unit.
Apple announced at Macworld Expo in January 2005 that Mercedes-Benz USA, Volvo, Nissan, Alfa Romeo and Ferrari would offer similar systems.[50][51][52]
Apple announced in September 2005 that they now have deals with Acura, Audi, Honda and Volkswagen to integrate iPod into their car stereos during the year. With these deals Apple now has 15 car companies worldwide planning to offer iPod integration. More than thirty percent of the cars in the United States now include iPod support. Honda will be the first to include speech-to-text capabilities that allow drivers to search for playlists, artist and album names or genre.[53][54]
Using adaptor kits such as Peripheral Electronics' iPod2Car or Densions IceLink, an iPod can be thus integrated into many vehicles which do not otherwise allow it. Almost any vehicle that has a factory CD changer controller port on the stereo can be integrated with an iPod using this kit. Adaptation, though not integration, can be obtained through the use of a cassette adaptor plugged into a vehicle cassette deck. This allows the vehicle to play the iPod's music, but not to control the iPod directly, such as the above mentioned methods allow. Finally, any after-market car stereo with RCA inputs can play the audio from an iPod by use of a "Y-adapter" that connects the RCA inputs on the stereo to the 1/8th inch stereo headset jack on the iPod.
Another common method of adaptation to a car can be achieved by using an FM transmitter, such as the iTrip. These allow the player to broadcast an FM signal, playable by car radios. Some FM transmitters also integrate charging from a car's cigarette lighter or power outlet.
Many aftermarket stereo manufacturers including Pioneer, Kenwood and Alpine have iPod integration solutions to allow one of their head units to control and play music from an iPod.
iPod sales
At the Macworld Expo keynote speech on January 10, 2006, Apple CEO Steve Jobs reported sales of over 42 million iPods total, and 14 million in the first quarter of fiscal year 2006. This equates to 100 iPods sold every minute throughout the quarter.[55]
Fortune magazine reported on June 27, 2005 that Apple had sold over 15 million iPods, including 5.3 million in the first quarter of that year.[56] The iPod currently dominates the digital audio player market in the US, frequently topping best-seller lists.[57] According to the latest financial statements, iPod's market share accounts for 74% in the US in July 2005. Within one year from January 2004 to January 2005, its US market share tremendously increased by 34% from 31% to 65%. This success was especially based on the introduction of the iPod mini, part of Apple's attempt to take market share from the mainstream Flash player market in the US. Flash players at the beginning of 2005 accounted for less than half the US market share that they did in 2004 (their market share decreased from 62% in January 2004 to 29% in January 2005).[58] In other countries, the iPod market share is significantly lower, mostly due to high import taxes and less ubiquitous marketing, so flash memory players, or hard disk based players from competitors like Creative are dominant.

In its first quarter results of 2006, Apple reported earnings of $565 million — its highest revenue in the company's history.[59] Apple shipped 6.16 million iPods during the quarter that ended on June 25, 2005, a 616% increase over the same quarter in 2004. Most recently, Apple shipped 14.04 million iPods during the quarter that ended on December 31, 2005, a 207% increase over the same quarter one year prior.[59]
On January 8, 2004, Hewlett-Packard announced that they would license the iPod from Apple to create an HP-branded digital audio player based on the iPod. The HP models were the same as the Apple iPod except for the inclusion of an "HP" logo on the back under the Apple logo and "iPod" label. They were sold as the "Apple iPod + hp". Retailers of this model included (among others) the retail giant Wal-Mart, which included a disclaimer explaining that it would not work with Wal-Mart's online music service. In July of 2005, HP reversed its decision and announced they would stop reselling the iPod by September 2005, when existing stock were projected to be depleted.[60] Sales by Hewlett-Packard made up 5% of all iPod sales.
iPod sales according to Apple's yearly financial results:

An iPod billboard in midtown Toronto.
iPod Lightrail Wrap AdvertisingApple has promoted the iPod and iTunes brands in several successful advertising campaigns, a large number of which are part of their series of silhouette commercials. The first iPod ad, featuring the tagline "A thousand songs, in your pocket" was launched alongside iPod in November 2001. The ad can be viewed on Apple's web site.[73]
In April 2003, Apple introduced a new ad campaign in conjunction with the launch of the iTunes Music Store. The ads featured informally dressed persons wearing iPods and giving animated silent renditions of popular songs, accompanied by dancing, air guitar, and other performances. The commercials featured a wide range of music, including The Who's My Generation, Sir Mix-a-lot's Baby Got Back, Pink's There You Go, and Eminem's Lose Yourself.
In October 2003, Apple released their first TV commercial of the silhouette campaign, which had already been featured for some time in print. It featured silhouettes dancing to music while listening to iPods. These commercials featured popular songs, such as The Vines' Ride, The Caesars' Jerk it Out, Gorillaz' Feel Good Inc., Steriogram's Walkie-Talkie Man, Jet's Are You Gonna Be My Girl, Propellerheads' Take California, Ozomatli's Saturday Night, N.E.R.D.'s Rock Star (Jason Nevin's Mix), Franz Ferdinand's Take Me Out, Daft Punk's Technologic, and many more. To commemorate the launch of the U2 iPod, Apple released an ad featuring a music video of Vertigo (featuring the band as characteristic iPod silhouettes).[74]
The iPod shuffle was released alongside TV commercials featuring silhouettes dancing on a green background with Apple's shuffle symbol moving underneath them, showing their intent on incorporating their silhouette campaign with each of their products. At the release of the iPod nano, a commercial was aired depicting pairs of hands turning over and examining the device, emphasizing its small size, and fighting over it. With the release of iPod with Video, a new commercial was released showing the new iPod's video playing capabilities. The ad featured U2's Original of the Species from the Vertigo: Live From Chicago DVD. Two more ads were released featuring Eminem and Wynton Marsalis. Although the ad still featured the silhouettes, Apple changed the background to an orange 'urban' theme in the Eminem version, and a 'cool' blue jazz look to the Wynton Marsalis variant.
On March 17, 2006, Apple released another new iPod ad. This ad departed from the traditional silhouette style, and featured thousands of CD covers pouring into an iPod nano. The ad again uses the tagline "1,000 Songs in Your Pocket," in reference to the original iPod launch ads. This commercial features the song "Cubicle" by the French electro rock band Rinôçérôse.

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