Electronics has had a major effect on the development of modern society.
The identification of the electron in 1897, along with the subsequent invention of the vacuum tube which could amplify and rectify small electrical signals, inaugurated the field of electronics and the electron age. This distinction started around 1906 with the invention by Lee De Forest of the triode, which made electrical amplification of weak radio signals and audio signals possible with a non-mechanical device. Until 1950, this field was called "radio technology" because its principal application was the design and theory of radio transmitters, receivers, and vacuum tubes.
The Segway PT is a two-wheeled, self-balancing transportation device invented by Dean Kamen and unveiled in December 2001. It is available in various models and form factors produced by the company Segway Inc. of New Hampshire. Computers and motors in the base keep the Segway upright at all times. Users lean forward to go forward, and back to move backwards. Segway PTs are driven by electric motors at up to 10.6 m/s (25.5 mph/40 km/h). Gyroscopes are used to detect departures from perfect balance.