How Television Works: Illustrated explanation of how early TVs worked.
Howstuffworks.com: How Television Works: Easy-to-read article that describes how television works.
Invention of Television: Tells how Philo Farnsworth created the first image dissector in 1927.
Radio Design Group: How Television Works: Brief introduction to the science behind electronic image transmission, satellite images, and high-definition TV.
Television History: The history of television invention from the black and white TV to color TV and digital TV. Includes information on some of the inventors along the way.
The American Experience: Big Dream Small Screen: Reveals the little-known story of the Utah farm boy who, at age 14, came up the idea of television. Includes a timeline of TV milestones. From PBS.