1947:
Transistors begin their life with the point-contact transistor. This was the very first transistor ever made, Walter Brattain was inventor of transistor in his invention his companion John Bardeen. It was made of two gold foil contacts sitting on a germanium crystal. Current passing through the transistors form one contact cause the germanium crystal to boost the strength of the current flowing through the other contact.
1948:
After the invention of point –contact transistor Bell came up and modified the point contact transistor to make it able to work consistently and was easier for mass production it was called Type-A transistor. This was the first transistor that Bell actually sold.
1951:
After a lot of research and study
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According to methods patterns are laid over the crystal, scientists are now able to etch away specific parts of the crystal, or add impurities to other parts as necessary. The first of these transistors, developed at Bell, left a little protrusion sticking out of the middle, and so they were named "mesa" transistors after the Spanish word for table. Later, Fairchild Semiconductor developed a version which was entirely flat -- these were called "planar" …show more content…
As a voltage is applied to this channel, it creates an electric field which acts like a faucet to turn on or off current through the rest of the transistor. MOSFETs were not originally better than the junction transistor, but they are much easier to make on an integrated circuit or microprocessor, and so they soon became the preferred type of transistor.
Advantages
1. Transistors have usually lower cost and are much smaller than tubes that’s why made the devices smaller and portable
2. Transistors can be combined in the millions on one cheap die to make an integrated circuit, whereas tubes are limited to at most three functional units per glass bulb. which makes the transistor more useful in increasing demand of components in complex circuits
3. Transistors don’t need any type of cathode heaters that why they have Lower power consumption, less waste heat, and high efficiency than equivalent tubes, especially in small-signal circuits.
4. Transistors can operate on lower-voltage for greater safety, lower costs, and portability
5. Transistors don’t need Matching transformers for low-impedance loads. Make them suitable for direct drive of many real world load