The Theory of Nothing

How did the transistor change the world?

How did the transistor change the world?

The invention of the transistor in 1947 at the Bell Labs changed everything and led to all of the modern digital electronic devices we use today. Up until this amazing event, all electronics had to use vacuum tubes. Transistors accomplish the same thing as vacuum tubes but with much less power consumption and at a much smaller size. The invention of the transistor led to the integrated circuit that has replaced transistors in modern electronic devices.

How does a transistor work? That’s a complicated question but its function is a result of quantum physics. A transistor is made out of semiconductor material like silicon. A semiconductor is what its name suggests--a material that has an electrical conductivity between a metal like copper and an insulator like glass. Most early transistors were what is called a bipolar transistor that has three terminals: a base, collector and emitter. A much weaker current applied to the base terminal can control a large current between the emitter and the collector terminals. That’s a terribly simplified explanation for a much more complicated process. The reason why I say this is because the electron conduction through a semiconductor involves the movement of electrons and holes. These two things are called charge conductors and are a product of the type of semiconductor used. Electrons are the charge conductor in n-type semiconductors and holes do that duty in p-type semiconductors. These types of semiconductor have to do with how the silicon is doped.

No, I don’t mean that they use drugs. Doping is done with impurities that change the conduction properties of the silicon. The action of a transistor is controlled by the way that the junction between the three terminals are electrically biased. In essence, the way that electrons are injected into the base-emitter junction affects the electrical flow from the emitter to the collector. Again, this is a simple explanation, but the result is an amplification effect.

Transistors come in various flavors. NPN and PNP type transistors involve the way that the semiconductors are doped. There is also a different type that is called a field-effect transistor. This unipolar transistor is even more efficient than the bipolar types and is instrumental in the invention of the integrated circuit. The MOSFET or metal-oxide-semiconductor transistor is the main form of this type and it has four terminals instead of the usual three. The main advancement in the FET is that it uses a gate insulator to increase the sensitivity of the transistor.

All of these improvements made it possible to manufacture smaller and more efficient transistors. As more improvements, including miniaturization, were made to the transistor the stage was set for the invention of the integrated circuit. The idea here was to stuff many transistors on a single silicon chip to produce complicated circuits such as a computer processor. We all owe gratitude to these previous developments in transistor technology for what we have today.

Thanks for reading.