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Invention of the Point Contact Transistor, 1954

Metal Grid Makes Magic

The vacuum tube was the predecessor to the transistor. A vacuum tube is a glass tube surrounding an area from which all gases have been removed, which area is known as a vacuum. In 1883, Thomas Edison discovered that a vacuum tube is able to conduct electricity when electrical contacts are attached to its end. A light bulb is an example of such a vacuum tube. In the 1900s, inventor Lee De Forest enabled the vacuum tube to meet its full potential when he invented the audion. The audion was able to conduct electricity in a particular direction, and furthermore was able to increase the electric current as it traveled. He achieved this feat by placing a metal grid in the middle of a vacuum tube. He introduced a second electric current into the vacuum tube in order to change the voltage on the grid, and was then able to control the flow of a second and more powerful current through the tube. This resulted in the emergence of a stronger current from the electrical base of the vacuum tube.

You can look over the patent issued for the "Three-Electrode Circuit Element Utilizing Semiconductive Materials" by clicking on the thumbnails at right.