A
television set is a device that combines a tuner, display, and speakers for the purpose of viewing
televisionTelevision is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
. Television sets became a popular consumer product after the Second World War, using
vacuum tubeIn electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
s and
cathode ray tubeThe cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...
displays. The addition of color to broadcast television after 1953 further increased the popularity of television sets, and an outdoor antenna became a common feature of suburban homes. The ubiquitous television set became the display device for the first generation of
home computerHome computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...
s.
Modern television sets incorporate liquid-crystal flat-screen displays, solid-state circuits, microprocessor controls and can interface with a variety of video signal sources, allowing the user to view broadcast and subscription cable TV signals or
Satellite televisionSatellite television is television programming delivered by the means of communications satellite and received by an outdoor antenna, usually a parabolic mirror generally referred to as a satellite dish, and as far as household usage is concerned, a satellite receiver either in the form of an...
, recorded material on
DVDA DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....
disks or
VHSThe Video Home System is a consumer-level analog recording videocassette standard developed by Victor Company of Japan ....
tape, or less common devices such as home security systems, and even over-the-air broadcasts received through an indoor or
outdoorA television antenna, or TV aerial, is an antenna specifically designed for the reception of over the air broadcast television signals, which are transmitted at frequencies from about 41 to 250 MHz in the VHF band, and 470 to 960 MHz in the UHF band in different countries...
antenna.
History
Mechanical televisionMechanical television was a broadcast television system that used mechanical or electromechanical devices to capture and display video images. However, the images themselves were usually transmitted electronically and via radio waves...
s were commercially sold from 1928 to 1934 in the United Kingdom, United States, and Russia. The earliest commercially made televisions sold by Baird in the UK in 1928 were radios with the addition of a television device consisting of a
neonNeon is the chemical element that has the symbol Ne and an atomic number of 10. Although a very common element in the universe, it is rare on Earth. A colorless, inert noble gas under standard conditions, neon gives a distinct reddish-orange glow when used in either low-voltage neon glow lamps or...
tube behind a mechanically spinning disk (patented by German engineer Paul Nipkow in 1884, see
Nipkow diskA Nipkow disk , also known as scanning disk, is a mechanical, geometrically operating image scanning device, invented by Paul Gottlieb Nipkow...
) with a spiral of apertures that produced a red postage-stamp size image, enlarged to twice that size by a magnifying glass. The Baird "Televisor" was also available without the radio. The Televisor sold in 1930–1933 is considered the first mass-produced television, selling about a thousand units.
The first commercially made electronic televisions with
cathode ray tubeThe cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...
s were manufactured by
TelefunkenTelefunken is a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the Allgemeine Elektricitäts-Gesellschaft...
in Germany in 1934, followed by other makers in France (1936), Britain (1936), and America (1938). The cheapest of the pre–World War II factory-made American sets, a 1938 image-only model with a 3-inch (8 cm) screen, cost US$125, the equivalent of
US$The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
1,863 in 2007. The cheapest model with a 12-inch (30 cm) screen was $445 ($6,633).
An estimated 19,000 electronic televisions were manufactured in Britain, and about 1,600 in Germany, before World War II. About 7,000–8,000 electronic sets were made in the U.S. before the
War Production BoardThe War Production Board was established as a government agency on January 16, 1942 by executive order of Franklin D. Roosevelt.The purpose of the board was to regulate the production and allocation of materials and fuel during World War II in the United States...
halted manufacture in April 1942, production resuming in August 1945.
Television usage in the United States skyrocketed after
World War IIWorld War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
with the lifting of the manufacturing freeze, war-related technological advances, the gradual expansion of the television networks westward, the drop in television prices caused by mass production, increased leisure time, and additional disposable income. While only 0.5% of U.S. households had a television in 1946, 55.7% had one in 1954, and 90% by 1962. In Britain, there were 15,000 television households in 1947, 1.4 million in 1952, and 15.1 million by 1968.
By the early 1970s,
color televisionColor television is part of the history of television, the technology of television and practices associated with television's transmission of moving images in color video....
had come into wide use.
Components
Modern televisions consist of a
displayA display device is an output device for presentation of information in visual or tactile form...
,
antennaAn antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
or
radio frequencyRadio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
(RF) input (a
TV aerial plugDomestic antenna plugs and sockets are devices that connect the TV set to the TV antenna so that TV signals can flow to them using a tuner .Antenna plugs are male antenna connectors that fit into female antenna sockets....
or an
F connectorThe F connector is a type of coaxial RF connector commonly used for "over the air" terrestrial television, cable television and universally for satellite television and cable modems, usually with RG-6/U cable or, in older installations, with RG-59/U cable. It was invented by Eric E...
), and a tuner. The existence of a television tuner (nowadays, a digital television tuner) in a display device distinguishes it from a
video monitorA video monitor also called a broadcast monitor, broadcast reference monitor or just reference monitor, is a display device similar to a television set, used to monitor the output of a video-generating device, such as playout from a video server, IRD, video camera, VCR, or DVD player. It may or...
— which receives signals that are already processed. Additionally TVs almost always include speakers and
teletextTeletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules...
. Most modern TVs also feature additional inputs for devices such as DVD players, video game consoles, and headphones; the most common types for analog audio and
analog videoAnalog video is a video signal transferred by an analog signal. An analog color video signal contains luminance, brightness and chrominance of an analog television image...
are
RCAAn RCA connector, sometimes called a phono connector or cinch connector, is a type of electrical connector commonly used to carry audio and video signals...
(for
composite videoComposite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...
and
component videoComponent video is a video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video information that is transmitted or stored as three separate signals...
), mini-DIN for
S-VideoSeparate Video, more commonly known as S-Video and Y/C, is often referred to by JVC as both an S-VHS connector and as Super Video. It is an analog video transmission scheme, in which video information is encoded on two channels: luma and chroma...
,
SCARTSCART is a French-originated standard and associated 21-pin connector for connecting audio-visual equipment together...
and D-terminal can be found in Europe and Japan respectively, the newer
HDMIHDMI is a compact audio/video interface for transmitting uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio frequency coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA...
(which can also connect to computers), USB and
BluetoothBluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
. Some high-end TVs have
EthernetEthernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
ports to receive information from the Internet, like stocks, weather, or news. Most TVs made since the early 1980s also feature an infra-red sensor to detect the signals sent by remote controls.
Display technologies
Televisions today use various
display technologiesDisplay Technologies is an industry leading point-of-purchase equipment supplier based in College Point, New York.- References :* http://www.display-technologies.com* http://www.imimerchandising.com/displaytech.htm...
such as
CRTThe cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...
, LCD,
PlasmaA plasma display panel is a type of flat panel display common to large TV displays or larger. They are called "plasma" displays because the technology utilizes small cells containing electrically charged ionized gases, or what are in essence chambers more commonly known as fluorescent...
, Digital Light Processing (DLP), and more recently OLED. Some front projectors, which feature TV tuners, can also be considered televisions.
Outdoor television
An
outdoor television set designed for outdoor use is usually found in the outdoor sections of
barA bar is a business establishment that serves alcoholic drinks — beer, wine, liquor, and cocktails — for consumption on the premises.Bars provide stools or chairs that are placed at tables or counters for their patrons. Some bars have entertainment on a stage, such as a live band, comedians, go-go...
s, sports fields, or other community facilities. Most outdoor televisions use
High-definition televisionHigh-definition television is video that has resolution substantially higher than that of traditional television systems . HDTV has one or two million pixels per frame, roughly five times that of SD...
technology. The screens are designed to remain clearly visible even in outdoor lighting. The screens also have anti-reflective coatings to prevent glare. They are weather-resistant and often also have anti-theft brackets. Outdoor TV models can also be connected with CD,
DVD playerA DVD player is a device that plays discs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. These devices were invented in 1997 and continue to thrive...
s and PVRs for greater functionality.
See also
- 3D television
A 3D television is a television set that employs techniques of 3D presentation, such as stereoscopic capture, multi-view capture, or 2D-plus-depth, and a 3D display – a special viewing device to project a television program into a realistic three-dimensional field.- History :In the late-1890's,...
- Active antenna
An active antenna is an antenna that contains active electronic components. This allows the construction of antennas of limited size and / or wide frequency range. Most active antennas use as antenna parts of minimal conducting area, e.g. a small whip, connected to the active component...
- Color killer
The color killer is an electronic stage in color TV receiver sets which acts as a muting circuit to cut off the color amplifiers when the TV receives a monochrome signal.- Monochromatic transmission :...
- Color television
Color television is part of the history of television, the technology of television and practices associated with television's transmission of moving images in color video....
- Digital video recorder
A digital video recorder , sometimes referred to by the merchandising term personal video recorder , is a consumer electronics device or application software that records video in a digital format to a disk drive, USB flash drive, SD memory card or other local or networked mass storage device...
- Divx
DivX is a brand name of products created by DivX, Inc. , including the DivX Codec which has become popular due to its ability to compress lengthy video segments into small sizes while maintaining relatively high visual quality.There are two DivX codecs; the regular MPEG-4 Part 2 DivX codec and the...
- DTV transition in the United States
The DTV transition in the United States was the switchover from analog to exclusively digital broadcasting of free over-the-air television programming...
- HDTV
- Home theater
A home theater or home theatre is a theater built in a home, designed to mimic commercial theater performance and feeling, more commonly known as a home cinema...
- Multiplier
The term multiplier may refer to:In electrical engineering:* Binary multiplier, a digital circuit to perform rapid multiplication of two numbers in binary representation* Analog multiplier, a device that multiplies two analog signals...
- Personal video recorder
- TV aerial plug
Domestic antenna plugs and sockets are devices that connect the TV set to the TV antenna so that TV signals can flow to them using a tuner .Antenna plugs are male antenna connectors that fit into female antenna sockets....
- Viera Cast
Viera Cast is a Smart TV platform by Panasonic that makes it possible to stream multimedia content from the Internet directly into select Viera HDTVs and Blu-ray disc players...
External links