ENIAC :

- “Electrical Numerical Integrator and Computer“. ENIAC, was the first general purpose electronic computer. The ENIAC was big it was, 30 tons and took up 1800 square feet of floor space. The ENIAC contained 6000 manual switches. The ENIAC was designed and built to calculate artillery firing tables for the U.S Army’s Ballistic Research Laboratory.

Vacuum Tube Size :

– In electronics, a vacuum tube is a device used to amplify, switch, otherwise modify, or create an electrical signal by controlling the movement of electrons in a low-pressure space. Some special function vacuum tubes are filled with low-pressure gas: these are so-called soft valves (or tubes), as distinct from the hard vacuum type which have the internal gas pressure reduced as far as possible. Almost all depend on the thermal emission of electrons, hence thermionic.

– The first generation computers were huge, slow, expensive, and often undependable.

- In 1946two Americans, Presper Eckert, and John Mauchly built the ENIAC electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I.

- The ENIAC used thousands of vacuum tubes, which took up a lot of space and gave off a great deal of heat just like light bulbs do.

- The ENIAC led to other vacuum tube type computers like the EDVAC (Electronic Discrete Variable Automatic Computer) and the UNIVAC I (UNIVersal Automatic Computer).

- The vacuum tube was an extremely important step in the advancement of computers. Vacuum tubes were invented the same time the light bulb was invented by Thomas Edison and worked very similar to light bulbs.

Transistors:

- There were obvious differences between the transistor and the vacuum tube.  The transistor was faster, more reliable, smaller, and much cheaper to build than a vacuum tube.

- One transistor replaced the equivalent of 40 vacuum tubes.

- These transistors were made of solid material, some of which is silicon, an abundant element (second only to oxygen) found in beach sand and glass.  Therefore they were very cheap to produce.

- Transistors were found to conduct electricity faster and better than vacuum tubes.  They were also much smaller and gave off virtually no heat compared to vacuum tubes.

Integrated Circuit (IC):

- The integrated circuit, or as it is sometimes

- in electronics, an integrated circuit (also known as IC, microcircuit, microchip, silicon chip, or chip) is a miniaturized electronic circuit (consisting mainly of semiconductor devices, as well as passive components) that has been manufactured in the surface of a thin substrate of semiconductor material. Integrated circuits are used in almost all electronic equipment in use today and have revolutionized the world of electronics.

referred to as semiconductor chip, packs a huge number of transistors onto a single wafer of silicon. Robert Noyce of Fairchild Corporation and Jack Kilby of Texas Instruments independently discovered the amazing attributes of integrated circuits.

- Placing such large numbers of transistors on a single chip vastly increased the power of a single computer and lowered its cost considerably.

Timex Sinclair:

- The keyboard is a ‘touch sensitive membrane’, a flexible plastic surface with the actual switches under the surface. While easy to clean and water resistant, it is very difficult and slow to type on, because you have to press hard and very deliberately to use the tiny, closely-spaced keys. Touch-typing is impossible. Resourceful users hacked into their system and added their own ‘real’ keyboard, external to the system.

First Home Computer: