amplifier

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What is an Amplifier?
An amplifier is an electronic device for increasing the amplitude of electrical signals. So basically an amplifier's job is to take a weak audio signal and boost it to create a signal that is powerful enough to drive a speaker. Amplifiers are used in many different audio systems today; including microphones, CD players, televisions and speaker systems.
How does it work?
There are many parts to an amplifier, but one of the most important parts is the transistor which consists of a piece of semiconductor. Before we go into how transistors work an understanding of semiconductors need to be established. What is a semiconductor? A semiconductor is a material that conducts a current but only partly, therefore it is halfway between an insulator (does not conduct electricity) and a conductor (conducts electricity). Typically, a semiconductor is made of a poor conductor, such as silicon, that has had impurities (atoms of another element) added to it; this process is called doping.
In pure silicon, all of the silicon atoms bond perfectly to their neighbours which leaves no space for the electrons to move about and conduct electricity. In doped silicon additional atoms change the balance; either adding free electrons or creating holes where electrons can go. There are two types of semiconductors; N-type is doped with phosphorus which adds free electrons (negative charge), and P-type is doped with boron to create holes (positive charge). Electrical charge moves when electrons move from hole to hole, so either one of these additions will make the material more conductive (Harris, 2002).
Now that we understand a bit more on semiconductors we can look at how transistors work:
How a transistor works
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... accuracy and sound quality. The class B amplifier needs transformers to run efficiently, and this is costly. On the other hand, the class A amplifier creates mass amounts of heat waste, and to lessen this impact cooling and heat regulating components have to be purchased; making the class A amplifier costly as well. With both of the amps being costly, the quality and efficiency of the amplifiers is the deciding factor. In a class B amp only half of the sine wave is reproduced by each transistor causing crossover distortion when the wave is cut-off. The makes the sound quality unclear and unpleasant to the ears. In a class A amplifier, a true reproduction of the original input wave is produced in the output making a pure sound quality. In result to this, I would definitely choose a class A amplifier over a class B amplifier due to the pure sound quality it produces.

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