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 powerful enough to drive a speaker. Today amplifiers are used in many different audio systems; including microphones, CD players, televisions and speaker systems. How does it work? An amplifier consists of many parts, but one of the most important parts is the transistor which consists of a piece of semiconductor. Before delving into how transistors work it is necessary to establish an understanding of semiconductors. What is a semiconductor? A semiconductor is a material that conducts current but only partially, so 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, to which impurities (atoms of another element) have been added; this process is called doping. In pure silicon, all the silicon atoms bond tightly to their neighbors, which leaves no room for electrons to move and conduct electricity. In doped silicon additional atoms change the equilibrium; either by adding free electrons or by creating holes where electrons can go. There are two types of semiconductors; The N-type is doped with phosphorus which adds free electrons (negative charge), while the P-type is doped with boron to create holes (positive charge). Electric charge moves when electrons move from one hole to another, so either of these additions will make the material more conductive (Harris, 2002). Now that we understand a little more about semiconductors, we can look at how transistors work:How a Transistor WorksThis is a picture of... middle of paper... precision and sound quality. The class B amplifier requires transformers to operate efficiently and this is expensive. On the other hand, the class A amplifier creates large amounts of waste heat and to reduce this impact it is necessary to purchase cooling and heat regulation components; making even the class A amplifier expensive. Since both amplifiers are expensive, the quality and efficiency of the amplifiers are the deciding factor. In a class B amplifier only half of the sine wave is reproduced by each transistor causing crossover distortion when the wave is clipped. This makes the sound quality unclear and unpleasant to the ears. In a class A amplifier, a faithful reproduction of the original input wave is produced in the output, creating pure sound quality. As a result, I would definitely choose a class A amplifier over a class B one for the sheer quality of sound it produces.