Invention
The tetrode tube was developed by Dr. Walter H. Schottky of Siemens & Halske GmbH in Germany in 1919. Thousands of variations of the tetrode design, as well as its later development the pentode, have been manufactured since then, although vacuum tubes in low-power equipment have been almost totally superseded by solid-state semiconductor devices.
Read more about this topic: Tetrode
Famous quotes containing the word invention:
“The public values the invention more than the inventor does. The inventor knows there is much more and better where this came from.”
—Ralph Waldo Emerson (1803–1882)
“The real writer is one
who really writes. Talent
is an invention like phlogiston
after the fact of fire.
Work is its own cure. You have to
like it better than being loved.”
—Marge Piercy (b. 1936)
“Heredity is a strong factor, even in architecture. Necessity first mothered invention. Now invention has little ones of her own, and they look just like grandma.”
—E.B. (Elwyn Brooks)