Air purifier
Air purifier is an essential component to maintaining an allergen free and healthy home. IQAir is the best all around air purifier especially for those with severe allergies; Blueair is superb as a quiet bedroom air purifier and inexpensive to run; AustinAir is a good, economical and durable air purifier; Allerair makes excellent air purifiers for smoke control or for multiple chemical sensitivities; Hamilton Beach has the best value for money; Airfree is a basement mold killer.

Amplifier
An amplifier can be considered to be any device that uses a small amount of energy to control a larger amount, although the term today usually refers to an electronic amplifier. The relationship of the input to the output of an amplifier — usually expressed as a function of the input frequency — is called the transfer function of the amplifier, and the magnitude of the transfer function is termed the gain. There are numerous types of electronic amplifier depending upon the application.The most common type of amplifier is the electronic amplifier, commonly used in radio and television transmitters and receivers, high-fidelity ("hi-fi") stereo equipment, microcomputers and other electronic digital equipment, and guitar and other instrument amplifiers. Its critical components are active devices, such as vacuum tubes or transistors.

Audio Receiver
In radio terminology, a receiver is an electronic circuit that receives a radio signal from an antenna and decodes the signal for use as sound, pictures, navigational-position information, etc. Radio and radio receiver are often used specifically for receivers whose output consists only of sound, although other types of receivers, such as television receivers, are technically radio receivers as well.As an appliance, "receiver" refers to a tuner, a preamplifier, and a power amplifier in chassis. Audiophiles will refer to such a device as an integrated receiver, while a single chassis that implements only the receiver function is called a discrete receiver.Some older receivers come with a loudspeaker. It is a common component in a high-fidelity or home-theatre system although some audiophiles believe that a separate tuner may provide superior reception and sound. The receiver is generally the nerve centre of a sophisticated home-theatre system providing selectable inputs for a number of different audio components like turntables, compact-disc players, and tape decks and video components like video-cassette recorders, DVD players, video-game systems, and televisions. Modern receivers tend to omit inputs for turntables and cassette decks and, instead, provide signal processors to give a more realistic illusion of listening in a concert hall. Digital audio S/PDIF connections are also common today.

Battery
In science and technology, a battery is a device that stores energy and makes it available in an electrical form. While such storage in an electrostatic form is practical in some specialized uses (in a capacitor), batteries consist of electrochemical devices such as one or more galvanic cells or more recently fuel cells, and may in the future use other technologies. The first possible evidence of batteries in history is the Baghdad Batteries from sometime between 250 BCE and 640 CE. The modern development of batteries started with the Voltaic pile developed by the Italian physicist Alessandro Volta in 1800 and has continued ever since. The battery industry generates 2.8 billion dollars in sales annually.

Boom Box
A boom box or boom box is a portable stereo system capable of playing radio stations or recorded music (usually cassettes) at relatively high volume. The synonym ghetto blaster or ghetto blaster is a term that can be considered insulting or complimentary depending on the context. The word ghetto blaster originated in the U.S., apparently reflecting the belief that such systems are popular in poor inner-city neighborhoods (ghettos), especially those populated by black Americans, whether as a sign of economic power or simply to play some music/throw a party. Ghetto blaster rather than boom box became the common term in the UK and Australia for large portable stereos, perhaps because it carried less meaning.

Calculator
Calculator is a device for performing numerical calculations. The type is considered distinct from both a calculating machine and a computer in that the calculator is a special-purpose device that may not qualify as a Turing machine. Although modern calculators often incorporate a general purpose computer, the device as a whole is designed for ease of use to perform specific operations, rather than for flexibility.The complexity of calculators varies with the intended purpose. A simple one with only four functions (addition, subtraction, multiplication and division and perhaps a single-number memory) may be useful for everyday activities such as shopping or checking a bill. More complex ones may include complex mathematical functions suitable to engineering or accounting as well as a substantial memory and the ability to execute moderately complex programs. Since the late-1980's, it has become common to incorporate simple calculators in other small devices, such as mobile phones, pagers or wrist watches.

Camcorder
A camcorder is a portable electronic device (generally a digital camera) for recording video images and audio onto a storage device. The camcorder contains both camera and recorder in one unit, hence its portmanteau name. This compares to previous technology where they would be separate. Camcorders are often classified by their storage device: VHS, Betamax, Video8 are examples of older, videotape-based camcorders which record video in analog form. Newer camcorders include Digital8, miniDV, DVD, and solid-state (flash) semiconductor memory, which all record video in digital form. (Please see the video page for details.) The imager-chip is considered an analog component, so the digital namesake is in reference to the camcorder's processing and recording of the video. Analog tapes lose quality slowly over time; "snow" becomes visible, while this does not happen with digital tapes. Either a certain block of digital data on the tape is readable or not, which means all or nothing. This leads to one of the most significant disadvantages of digital recording - which minor disc errors can lead to corruption of the entire disc. No data from a block on the tape means a block artifact which is visible in the picture, but they can be interpolated from surrounding data like it happens in CD-Players when a read error occurs.

Cell phone
A mobile phone or cell phone is an electronic telecommunications device with the same basic capability as a conventional fixed-line telephone, but which is also entirely portable and is not required to be connected with a wire to the telephone network. Most current mobile phones connect instead to the network using a wireless radio wave transmission technology. The mobile phone communicates via a cellular network of base stations, also known as cell sites, which are in turn linked to the conventional telephone network. Some of the world's largest mobile phone manufacturers include Alcatel, Audiovox, Fujitsu, Kyocera (formerly the handset division of Qualcomm), LG, Motorola, NEC, Nokia, Panasonic (Matsushita Electric), Philips, Sagem, Samsung, Sanyo, Sharp, Siemens, SK Teletech, Sony Ericsson, and Toshiba. Mobile phones are often packed with features that offer users far more than just the capability to send text messages and make voice calls. These may include: Internet browsing, music (MP3) playback, personal organizers, e-mail, watch/alarm, built-in cameras and camcorders, ringtones, security measures (e.g. pin codes), SIM blocks, games, radio, Push To Talk (PTT), infrared and bluetooth connectivity, call registers, and ability to watch streaming video or download video for later viewing.

Cordless telephone
A cordless telephone or portable telephone is a telephone with a wireless handset which communicates with a base station connected to a fixed telephone landline (POTS) via radio waves and can only be operated close to (typically less than 100 metres of) its base station, such as in and around the house. Unlike a standard telephone, a cordless telephone needs household mains electricity to power the base station. The cordless handset is powered by a battery which is recharged by the base station when the handset is connected to the base station when not in use. Over time, the battery may need to be replaced as it does not get recharged properly or for a sufficient amount of time. Typically, cordless handset batteries last for about an year although much depends on how frequently it is charged-discharged and also the average usage. Once a month, one should leave the handset off the base station so that the battery is completely discharged before getting charged again (unless the manual gives other instructions). Also, the charge contacts on both the base and the handset should occasionally be cleaned with a pencil eraser. There are also some advanced cordless phone systems that can operate without power. In the event of a power outage, the phone will convert itself into a standard telephone that gets its power from the landline. However, in this mode, only a handset attached directly to the base could work. All wireless handsets would not function.

Clock
A clock (from the Latin cloca, "bell") is an instrument for measuring time. A clock is usually a physical instrument; an especially accurate one is called a chronometer. The clock in its modern form (24 hour clock) has been in use since at least the 14th century. Clock can refer to an abstract system of time measurement (see calendar for other measurements). Modern clocks define constant units of time: an hour is always sixty minutes, of sixty seconds each.

Dictionary
A dictionary is a list of words with their definitions, a list of characters with their glyphs, or a list of words with corresponding words in other languages. In some languages, words can appear in many different forms, but only the lemma form appears as the main word or headword in most dictionaries. Many dictionaries also provide pronunciation information; grammatical information; word derivations, histories, or etymologies; illustrations; usage guidance; and examples in phrases or sentences. Dictionaries are most commonly found in the form of a book.

Digital Camera
A digital camera, is an electronic device to transform images into electronic data. Modern digital cameras are typically multifunctional and the same device can take photographs, video, and/or sound Digital still cameras are cameras whose primary purpose is to capture photography in a digital format. Initially, a digital camera was characterized by the use of flash memory and USB or FireWire for storage and transfer of still photographs, and this is still the common meaning of the unadorned term. However, modern digital photography cameras have a video function, and a growing number of camcorders have a still photography function. In addition, some newer camcorders record video directly to flash memory and transfer over USB and FireWire. Among digital still cameras, most have a rear LCD for reviewing photographs. They are rated in megapixels; that is, the product of their maximum resolution dimensions in millions. The actual transfers to a host computer are commonly carried out using the USB mass storage device class (so that the camera appear as a drive) or using the Picture Transfer Protocol and its derivatives. All use either a CCD (Charge-Coupled Device) or a CMOS sensor, i.e. chips comprised of a grid of phototransistors to sense the light intensities across the plane of focus of the camera lens. CMOS (Complementary Metal-Oxide Semiconductor) sensors are differentiated from CCDs proper in that it uses less power and a different kind of light sensing material, however the differences are highly technical and many manufacturers still consider the CMOS chip a charged coupled device. For our purposes, a chip sensor is a CCD

Electronic Amplifier
An electronic amplifier is a device for increasing the current, voltage or power of a signal. It does this by taking power from a power supply and controlling the output to match the input signal shape but with a larger amplitude. This process invariably introduces some noise and distortion into the signal, and the process cannot be 100% efficient. Therefore amplifiers will always produce some waste heat. An idealized amplifier can be said to be "a piece of wire with gain", as the output is an exact replica of the input, but larger.

Electronic Clock
Electronic clock to provide a coded time signal for a timing channel on a magnetic tape recorder is described. The clock provides a direct means of determining the elapsed time, whereas more commonly employed methods of timing do not. The construction of the clock is made practical by the use of integrated circuitry which ensures that it is both compact and low on power consumption.

Geiger Counter
A Geiger counter, also called a Geiger-Müller counter, measures ionizing radiation. Geiger counters can be used to detect alpha, beta, and under some conditions gamma radiation (but not reliably), but not neutrons. Due to the fact that the density of the gas is so low, it is unlikely that a gamma photon will interact with the gas in a GM tube, hence the GM tube is very insensitive to gamma rays. A much better device for detecting gamma rays is a sodium iodide scintillation counter . The window on the scintillation counter is too thick to allow beta particles to enter the detector. It is vital that the correct detector is chosen for the radiation which is to be tested for.

Home Automation
Home automation depends on communications protocols which are created to control the various electrical and electronic systems in your house. There are four main home automation players out there, each a little different, and they're not all compatible with each other.X-10 is a well-established home automation technology more than 30 years old. With X-10, there's no need for new wiring because it transmits signals over electric power lines. However, this can make it susceptible to interference. One good thing about X-10 is that its control devices are available many places and at reasonable rates.

Home Theater System
Home cinema, also called home theater, seeks to reproduce cinema quality video and audio in the home. The video aspect usually involves a large-screen and/or high definition television or a projection system with movie screen to project the image on. Quality audio reproduction is usually achieved with a high fidelity surround sound system.Technically, a home cinema could be as basic as a simple arrangement of a television, VCR, and a set of speakers. It is therefore difficult to specify exactly what distinguishes a "home cinema" from a "television and stereo". Most people in the consumer electonics industry would agree that a "home theater" is really the integration of a relatively high-quality video source with multi-channel electronics and speakers. Even if households have the system set up for home cinema it is common only to use the speakers integrated within the television rather than to play the sound through the surround sound system. This is because surround sound loses its impact with material which is not recorded in a way suitable for surround sound. Films, drama and sport tend to be optimised for surround sound whereas news and daytime TV provide no particular advantage.

Image Scanner
In computing, a scanner is a device that analyzes a physical image (such as a photograph, printed text, or handwriting) or an object (such as an ornament) and converts it to a digital image.Most scanners today are variations of the desktop (or flatbed) scanner. Hand-held scanners, where the device is moved by hand, were briefly popular but are now not used due to the difficulty of obtaining a high-quality image. Both these types of scanners use a charge-coupled device (CCD) as the image sensor, whereas a drum scanner uses a photomultiplier tube as the image sensor.Other types of scanners are planetary scanners, which take photographs of books and documents, and laser range scanners, for producing three-dimensional models of objects.

LCD TV
LCD (liquid-crysal display) is the best solution if you don´t have much space. LCD sets are more readily available in smaller sizes than plasma. However,these sets don´t offer a wide viewing angle,nor are they ideal for fast motion like sports or videogames. If you want to use these things as well choose an LCD with a response time below 12 miliseconds.A liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is prized by engineers because it uses very small amounts of electric power, and is therefore suitable for use in battery-powered electronic devices.

Metal Detector
Metal detectors use electromagnetic induction to detect metal. In 1881, Alexander Graham Bell constructed a crude metal detector in an attempt to find an assassin's bullet in President James Garfield. Gerhard Fischar patented a portable version in 1931.Upright "archway" detectors are used at entrances to secured buildings, such as courthouses or airports, to detect metallic weapons which may be brought in. Small portable "wand" detectors are used by security staff to frisk persons for the same. Larger portable metal detectors are used by treasure hunters to locate metallic items, such as jewelry or coins, buried shallowly under ground. There are three types of metal detectors: beat frequency oscillator, induction balance, and pulse induction.

MP3 Player
MP3 players are audio players that play music files under audio file formats. Most, if not all, digital audio players can play music that has been ripped from Compact Discs via computer. In addition to ripped CD tracks, many digital audio players can accept downloaded music from online music stores. However, due to the complexity of DRM, not all audio file formats will play on certain digital audio players. Some proprietary audio file formats will also restrict users from transferring songs to non-compatible digital audio players.

Night Vision Goggles
Night vision goggles (NVG) are a type of optical instrument that allows one to see in the dark. They are most often used by the military. There are three common types of night vision goggles:
Passive night vision goggles— these pick up any light in the given area and amplify it several thousand times using an image intensifier. This works by the photoelectric effect. As a photon collides with a detector plate, the metal ejects several electrons that are then amplified into a cascade of electrons that light up a phosphor screen. Often a dim star in the sky is enough to illuminate an entire field. This type is commonly used for war reporting, tinting the picture green. The color green is chosen because the human eye is most sensitive and able to discern the most shades in green.Active night vision goggles— these project infrared light (the same type used by a remote control), and produce an image from the light reflected back. These goggles may require an image enhancer to amplify the light. This feature is commonly found on home video cameras, as it suits most consumers’ needs for seeing in the dark. Pointing a television remote control at this type of system produces a glaringly bright image.Heat-sensing or infrared goggles— these show anything that emits normal heat radiation in the given area.

Portable DVD Player
A DVD player is a device for playing video DVDs. Most hardware DVD players have to be connected to a television set; however, portable DVD players need not be connected because it comes with an LCD screen that makes it more convenient for people on the go.Portable DVD players, like Most DVD players also allow users to play audio CDs (CDDA, MP3, etc.) and Video CDs (VCD) and include a home cinema decoder (i.e. Dolby Digital, Digital Theatre System (DTS)). Some newer devices also play videos in the DivX video compression format popular on the internet.

Radar Detector
A radar detector is an electronic device used by motorists to determine if their speed is being monitored. The term originates from early speed-detection technologies, in which police bounced a radio wave off a moving vehicle with a device called a radar gun that determined the vehicle's speed by the Doppler-effect-moderated change in the wave's frequency. Most of today's radar detectors detect signals across a variety of wavelength bands - usually X, K, and Ka bands (and Ku, in Europe).Newer speed-detection technology uses pulsed laser light (LIDAR, commonly referred to as laser detection) rather than radio waves. Modern "radar detectors" have been adapted to suit that technology, by detecting the infrared light emitted by these new detection methods. LIDAR detection is not nearly as reliable as the detection of radar, since the light is much more focused and often aimed below the windscreen level, where the detector is usually mounted. (The reflective coating of the vehicle licence plate is an excellent laser beam reflector.)

Speaker
A loudspeaker, or simply speaker, is an electromechanical transducer which converts an electrical signal into sound. The term loudspeaker is used to refer to both the device itself, and a complete system consisting of one or more loudspeaker drivers (as the individual units are often called) in an enclosure. The loudspeaker is the most variable element in an audio system, and is responsible for marked audible differences between systems.Speakers can be classified as either Woofers,Mid Ranges, Tweeters, Full Ranges and Sub Woofers depending on the type of sound and frequency they produce.

Spectrum Analyzer
A spectrum analyzer is a device used to examine the spectral composition of some electrical, acoustic, or optical waveform. Often, it measures the power spectrum.An analogue spectrum analyzer uses either a variable bandpass filter whose mid-frequency is automatically tuned (shifted, swept) through the range of frequencies of which the spectrum is to be measured or a superheterodyne receiver where the local oscillator is swept through a range of frequencies. A digital spectrum analyzer uses the Fast Fourier Transform (FFT), a mathematical process that transforms a waveform into the components of its frequency spectrum. As a result, computer programs can compute such transforms, and makes audio processing easier. FFTs have applications in much wider fields. Some spectrum analyzers (such as Tektronix's family of "Real Time spectrum analyzers") use a hybrid technique where the incoming signal is first down-converted to a lower frequency using superheterodyne techniques and then analyzed using FFT techniques.

Surveillance
Systems Surveillance is the process of monitoring the behavior of people, objects or processes within systems for conformity to expected or desired norms in trusted systems for security or social control. See also, deviation analysis. "Sur-Veillance" is French for to "watch from above". Note the all seeing "eye-in-the-sky" in this London Transport poster. Although the word surveillance literally means (in French) "to watch from above" (i.e. a God's-eye view looking down from on-high) the term is often used for all forms of observation or monitoring, not just visual observation. Nevertheless, the all-seeing eye-in-the-sky is still a general icon of surveillance. The word surveillance is commonly used to describe observation from a distance by means of electronic equipment or other technological means.

Timer
A timer is a specialized type of clock. A timer can be used to control the sequence of an event or process. Timers can be mechanical, electromechanical, digital, or even software, since most computers have clocks. Early mechanical timers used typical clockwork mechanisms, such as a escapement and spring to regulate their speed. Inaccurate, cheap mechanisms use a flat beater that spins against air resistance. Mechanical egg-timers are usually of this type more accurate mechanisms resemble small alarm clocks. The chief advantage of these is that they require no battery, and can be stored for long periods of time. The most widely-known application is to control explosives.

WebTV
MSN TV (formerly WebTV) is an Internet appliance developed by the Microsoft TV subsidiary of Microsoft Corporation. The appliance attaches to a television and provides proprietary dial-up Internet access. WebTV Networks was founded by three veterans of Apple Computer and General Magic, Steve Perlman, Bruce Leak and Phil Goldman, in the summer of 1995. The company was originally named Artemis to disguise the nature of their business. Early versions of the device were built with ease-of-use and low cost as their primary design considerations, and were aimed at bringing the Internet to senior citizens and those without an Internet connection or personal computer. WebTV Networks was purchased by Microsoft for $425 million dollars USD in April 1997, before the company was even two years old. The first WebTV device featured a proprietary operating system, file system, and a web browser based on the Spyglass Mosaic web browser in just two megabytes of flash memory. No hard drives were present in these WebTV Classic boxes. The software was comprised of a TCP/IP stack, HTML rendering engine, JavaScript interpreter, audio engine (MP3, MIDI, Real audio, and WAV), and video engine (Flash and MPEG). Video rendering for the television was done by the proprietary "Solo" chip so the low-end MIPS CPU could be freed up to process web pages. WebTV "Classic" units originally had 112 MHz chips with the "Plus" units having 167 MHz chips.

Universal Remote Control
A Universal Remote is a Remote Control that can be programmed to operate various brands of one or more types of consumer electronics devices (i.e. TV, VCR, DVD, Cable/Satt.. Box, etc.). Low end universal remotes can only control a set number of devices determine by their manufacturer while mid and high end universal remotes allow the user to program in new controls codes to the remote. Many remotes sold with various electronic devices these days include a universal remote capabilities for other types of devices to allow the remote to control other devices (of various brands) beyond the device it came with (i.e. A VCR remote that can be programed operate various brands of televisions).

USB Flash Drive
A USB flash drive is essentially NAND-type flash memory integrated with a USB 1.1 or 2.0 interface used as a small, lightweight, removable data storage device of up to 16 GB (as of 2006). Depending on the drive type and OS version, and in some cases what patches are installed, the drives generally work with Windows 98/ME/2000/XP (Windows 98 requires a driver to be installed; often, inconveniently, a specific driver for each type of flash drive), Macintosh, Linux, and other Unix-like platforms that support USB. USB flash drives are also known as "pen drives", "thumb drives", "flash drives", "USB keys", and a wide variety of other names. A flash drive consists of a small printed circuit board encased in a robust plastic or metal casing, making the drive sturdy enough to be carried about in a pocket, as a keyfob, or on a lanyard. Only the USB connector protrudes from this protection, and is usually covered by a removable cap. Most flash drives feature the standard type-A USB connection allowing them to be connected directly to the port. Some small drives have been made with a thin plug designed to mate with a standard USB port but these are very rare. Flash drives are impervious to the scratches and dust that plagued previous forms of portable storage like compact discs and floppy disks, and their durable solid-state design means they often survive casual abuse (impacts, being dropped or crushed, run through a washing machine, or even dropped in coffee). This makes them ideal for transporting personal data or work files from one location to another (such as from home to school or office) or for carrying around personal data that the user typically wants to access in a variety of places.