Evolution of the Transistor!

The Basics

So, what is a transistor? A transistor is a semi-conductor. A semi-conductor (in simple terms) doesn't allow as much electricity to pass through it as a regular conductor. It can be used in many ways. It can amplify (or enlarge) the amount electricity from point A to point B. it can also be used as a switch, but that's a different lesson.

The First Transistor

The first transistor was a huge achievement for human science. It layed the foundation for all sorts of other transistor that we have today! (Field effect transistor, junction transistor [PNP,NPN] etc.) It was comprised of a slab of Germanuim, A base, collection, and emmiter wire, and some gold foil touching the Germanium. I won't go into excruciating detail but to put it in simple terms it amplified the current running from point A to point B.

The Next Step

In 1948 Bell labs simplified the transistor and made the "Type-A" transistor. It was the first transistor that could be mass produced and sold. It was still a point contact transistor but the others were coming.

The Junction Transistior

In 1951 William Shockley came up with the junction transistor. This is the transistor that you will probably see and might use today. It is made of up 3 inputs/outputs. The Base, emmitter, and collector. Depending on the type , PNP or NPN* it can act as a switch or an amplifier.** A weak volatge cooming in the center layer of the sandwitch could affect another current travelling across the entire sandwitch.




* A PNP and NPN transistor are similar but (as shown in pic) use different inputs/outputs on certian parts.

**Both NPN and PNP transistors can act as a switch or amplifier. I just wanted to clear any confusion.

1956 Evolution

Bell Labs came with a new transistor that is entirely flat. These new transistors were called planar transistors.

Germanium ---> Crystal

In 1958 scientists figured out that Germanium transistors stopped worknig at high temperatures, so they replaced them with crystal (like the crystal in our LCD [Liquid crystal Display] TVs. This allowed transistors to be able to handle more Volatge and more Amperage.

http://www.pbs.org/transistor/background1/events/trnsevolution.html *****

The MOSFET

The next large jump in tansistor technology was the MOSFET (Or Metal-Oxide-Semiconductor Field-Effect Transistor) Instead of a silicon sandwich it has a channel. When voltage is applied to the channel it creates a magnetic field that turns the transistor "on".

Final Words

Transistor tech has improved greatly since when they were first created. They've gotten smaller and more efficient. Now instead of setting up a 1ft tall germanium circuit you can just plug in a little chip. Everything electronic today most likely has at least 1 if not more transistors and they all started w/ a hunk of germanium and an idea.