It is a semiconductor device used to amplify and switch electronic signals and electrical power and it is composed of semiconductor material with at least three terminals for connection to an external circuit.
The Semiconductor Transistor. The modern electronic 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. Transistors are composed of three parts, called 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. Anatomy of a Transistor. Before we go into the physical limitations of transistors, it helps to know what a transistor is made of and what it actually does. Basically, a transistor is a switch made out of a special kind of matter. One way you can classify matter is by looking at how well it can conduct electricity. That divides matter into three categories: conductors, insulators and semiconductors. a transistor is a device composed of semiconductor material john bardeen walter brattain william shockley all co invented the transistor in 1947 at bell labs  A transistor is a three-terminal electronic component composed of semiconducting material such as silicon or germanium.   the purpose of a transistor is to use a small sign … al to vary the conductivity of a piece of semiconductor. The tiny signal can switch a large current on and off. Or, the signal can be used to control a larger signal, so the transistor becomes an amplifier. Because in this device the resistsnce between two terminale respectively collector and emitter is changed by changing the base voltage that is it transfers the resistance betw … een emitter and collector therefore it is called as TRANSISTOR.(TRANSFER OF RESISTOR) Not exactly. Name. Vacuum tubes were made containing several three terminal devices called triodes. The transistor is a three terminal, solid state electronic device. In a three terminal device we can control electric current or voltage between two of the terminals by applying an electric current or voltage to the third terminal.  1 Transistors are made of chemical elements in Group IV in the periodic table of elements. 2  Most commonly Silicon is used; Germanium is less common. 3  These elements form crystals in such a way that the four valence electrons of each atom are shared between neighbors.  The Bipolar Junction Transistor (BJT) was invented by three scientists, William Shockley, John Bardeen and Walter Brattain, in 1948. They all worked at Bell Labs, and were tr … ying to find something to replace the bulky and heat wasting vacuum tubes. Because in this device the resistsnce between two terminale respectively collector and emitter is changed by changing the base voltage that is it transfers the resistance betw … een emitter and collector therefore it is called as TRANSISTOR.(TRANSFER OF RESISTOR) Not exactly. Name. A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit. The ratio of these currents varies depending on the type of transistor, and even for a particular type, varies depending on the collector current. In the example light-switch circuit shown, the resistor is chosen to provide enough base current to ensure the transistor will be saturated. A device composed of semiconductor material that amplifies a signal or opens or closes a circuit. Invented in 1947 at Bell Labs, transistors have become the key ingredient of all digital circuits, including computers. Today's microprocessors contains tens of millions of microscopic transistors. 
http://history-computer.com/ModernComputer/Basis/transistor.html http://computer.howstuffworks.com/small-cpu1.htm http://inventors.about.com/od/computersandinternet/a/What-Is-A-Semiconductor.htm http://www.answers.com/Q/What_is_a_transistor_composed_of http://www.nobelprize.org/educational/physics/transistor/history/ http://thalia.spec.gmu.edu/~pparis/classes/notes_101/node99.html http://www.answers.com/Q/What_is_a_transistor_composed_of https://en.wikipedia.org/wiki/Transistor http://www.webopedia.com/TERM/T/transistor.html
what is a transistor composed of