Why were vacuum tubes used in first generation computers?

Answer 1

I did't find anywhere that it was when I researched it.

Over 99% of computers built from 1940 to 1958 used vacuum tubes as their active elements for: logic, power supply, memory sense/drive, etc. circuits. Other computers at this time were electromechanical, magnetic, and a small number of experimental transistor computers were built.

From 1959 to about 1965 most computers used transistors as their active elements for: logic, power supply, memory sense/drive, etc. circuits. A small number off computers at this time were magnetic or used primitive monolithic ICs.

From 1964 on more and more computers used ICs, of progressively increasing density.

Answer 2

The first programmable computer was the electro-mechanical Z1 in 1936. The first digital computer was Atanasoff-Berry Computer (ABC) in 1937 (using vacuum tubes) and the first electric programmable computer was Colossus in 1943.

Transistors (which replaced vacuum tubes) did not exist until 1947.

Answer 3

The vacuum tube can be used as any of the following:

• amplifier
• switch
• rectifier
• logic gate
• display
• dram
• light sensor
• voltage/current regulator
• etc., etc.

Answer 4

For the same reason they used vacuum tubes for radios, TVs, phonographs, etc. at the same time: they were the only electronic components available that could amplify signals. In the late 1950s there was a brief period where magnetic amplifiers were perfected and a few computers were built using them, but the transistor quickly became faster, smaller, and lower power than either vacuum tubes or magnetic amplifiers; so there was no computer generation based on magnetic amplifiers. Transistors were introduced into radios, TVs, phonographs, etc. somewhat later than computers because the early transistors were too expensive for cheap consumer products.