1. Transistors
On November 17, 1947, Walter Brattain dumped his whole experiment into a thermos of water. The silicon contraption he'd built was supposed to help him study how electrons acted on the surface of a semiconductor -- and why whatever they were doing made it impossible to build an amplifier. But condensation kept forming on the silicon and messing up the experiment. To get rid of that condensation, Brattain probably should have put the silicon in a vacuum, but he decided that would take too long. Instead he just dumped the whole experiment under water -- it certainly got rid of the condensation!
Out of the blue, the wet device created the largest amplification he'd seen so far. He and another scientist, Robert Gibney, stared at the experiment, stunned. They began fiddling with different knobs and buttons: by turning on a positive voltage they increased the effect even more; turning it to negative could get rid of it completely. It seemed that whatever those electrons had been doing on the surface to block amplification had somehow been canceled out by the water -- the greatest obstacle to building an amplifier had been overcome.

2. Electronic Transistor >Solid Semiconductor Material >Amplify Electronic Signals >Switch Electronic Signals
A transistor is a semiconductor device commonly used to amplify or switch electronic signals. A transistor is made of a solid piece of a semiconductor material, with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled power can be much larger than the controlling power, the transistor provides amplification of a signal.

3. Transistor Design >Gate (Valve) >Controls Supply of Electricity
design of a transistor allows it to function as an amplifier or a switch. This is accomplished by using a small amount of electricity to control a gate on a much larger supply of electricity, much like turning a valve to control a supply of water.

4. Transistors Key Parts >Base >Collector >Emitter
Transistors are composed of three parts – a base, a collector, and an emitter. The base is the gate controller device for the larger electrical supply. The collector is the larger electrical supply, and the emitter is the outlet for that supply. By sending varying levels of current from the base, the amount of current flowing through the gate from the collector may be regulated. In this way, a very small amount of current may be used to control a large amount of current, as in an amplifier. The same process is used to create the binary code for the digital processors but in this case a voltage threshold of five volts is needed to open the collector gate. In this way, the transistor is being used as a switch with a binary function: five volts – ON, less than five volts – OFF.

5. Transistors Types >Junction >Field Effect
There are two main types of transistors-junction transistors and field effect transistors. Each works in a different way. But the usefulness of any transistor comes from its ability to control a strong current with a weak voltage. For example, transistors in a public address system amplify (strengthen) the weak voltage produced when a person speaks into a microphone.