Vacuum tube
Alternatively
referred to as an Electron tube, a Vacuum tube was first developed
by John Ambrose Fleming in 1904 and is a glass tube that has had all gas has been removed creating a vacuum. Vacuum tubes
contain electrodes for controlling electron flow in early computers that used
them as a switch or an amplifier. In the picture to the right, is a collection of different vacuum tubes to give you a
better understanding of what these look like. Today, vacuum tubes are no longer used
with computers and have been replaced by the transistor.
Also see: Electronics definitions, Nixie tube, Selectron tube, Transistors, Williams Tube