Television

Introduction
The development of television systems
- Mechanical systems
- Electronic systems
- Colour television
- Digital television
Principles of television systems
- The television picture
  - Human perception of motion
  - Image analysis
    - Flicker
    - Resolution
    - Picture shape
    - Scanning
  - The scanning pattern
    - Interlaced lines
    - Deflection signals
    - Synchronization signals
  - The picture signal
    - Wave form
    - Distortion and interference
    - Bandwidth requirements
- Compatible colour television
  - Basic principles of compatible colour: The NTSC system
  - European colour systems
    - PAL
    - SECAM
- Digital television
- Television transmission and reception
  - Transmission
    - Generating the colour picture signal
    - The carrier signal
    - The sound signal
    - The television channel
    - Broadcast television
    - Cable television
    - Direct broadcast satellite television
    - Teletext
  - Reception
    - Basic receiver circuits
    - Controls
- Television cameras and displays
  - Camera image sensors
    - Electron tubes
    - Charge-coupled devices
  - Displays
    - Picture tubes
      Basic structure
      Electron guns
      Deflection coils
      Shadow masks and aperture grilles
    - Liquid crystal displays
    - Plasma display panels
- Video recording
  - Magnetic tape
  - Video discs
  - Special techniques
  - Flying spot scanner
  - Motion-picture recording
    - The continuous projector
    - The intermittent projector

References & Edit History Related Topics

Images & Videos

Diagram of a color television picture tube using the shadow-mask technique, showing red, green, and blue electron beams from electron guns passing through an aperture grille to strike phosphor-coated glass, with labeled parts and a close-up of the grille structure.

Side-by-side screens: left, vintage TV with black-and-white party scene labeled then; right, still from the Apple TV+ series Severance labeled now.

John Logie Baird with television transmitter

Philo Farnsworth

Labeled diagram of an iconoscope television camera tube showing internal components including the electron gun, deflecting coils, anode, mosaic, signal plate, and scanning beam path.

production line for the RCA CT-100 television

Side-by-side comparison of standard-definition TV (SDTV) and high-definition TV (HDTV) aspect ratios using an image of an airplane. The SDTV screen is 4 units wide by 3 units tall, while the HDTV screen is 16 units wide by 9 units tall. Both screens show dashed rectangles indicating the safe action area (90 percent) and safe title area (80 percent) within the frame.

Diagram showing interlaced scanning in television: the top left image displays A lines from the first field, the top right shows B lines from the second field filling in the gaps, and the bottom image combines both fields to form a complete picture of an airplane.

Diagram illustrating sequential parallel-line scanning with two graphs: one showing a zigzag horizontal deflection wave form and another showing a sawtooth vertical deflection wave form, both corresponding to the scanning pattern on a rectangular screen.

At a Glance

Vintage TV set

television summary

Diagram of a color television picture tube using the shadow-mask technique, showing red, green, and blue electron beams from electron guns passing through an aperture grille to strike phosphor-coated glass, with labeled parts and a close-up of the grille structure. — colour television picture tube At right are the electron guns, which generate beams corresponding to the values of red, green, and blue light in the televised image. At left is the aperture grille, through which the beams are focused on the phosphor coating of the screen, forming tiny spots of red, green, and blue that appear to the eye as a single colour. The beam is directed line by line across and down the screen by deflection coils at the neck of the picture tube.

Television

mass media

Written by

A. Michael NollAll

Fact-checked by

Britannica Editors

Last updated

Nov. 13, 2026 •History

Television (TV), a form of mass media based on the electronic delivery of moving images and sound from a source to a receiver. By extending the senses of vision and hearing beyond the limits of physical distance, television has had a considerable influence on society. Conceived in the early 20th century as a possible medium for education and interpersonal communication, it became by mid-century a vibrant broadcast medium, using the model of broadcast radio to...

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