Theory of the experiment Lab Report Example | Topics and Well Written Essays - 1750 words

Theory of the experiment - Lab Report Example This can be said to be a compromise between the Class A amplifiers and the Class B amplifier topologies. These amplifiers combines the sound quality provided by the class A simplifiers and the efficiency provided by the Class B amplifiers. This is achieved by having both transistors biased to have them conduct a signal close to zero. Figure 1.3 shows a class AB amplifier and its associated input and output waveforms. When small signals are applied, both transistors will be active, making the amplifier to function like a Class A amplifier. When a large signal is applied, only one transistor becomes active. This makes the amplifier to operate like a Class B amplifier. Class AB speaker amplifiers gives a high SNR and a low THD+N. they are also about 65% efficient. These amplifiers are used in making portable media players, tablets, cameras, and so on where high fidelity is required.Class D amplifiersThese amplifiers use PWM (pulse width modulation) to produce a rail to rail output signa l. This signal has a variable duty cycle that is used to approximate the input signal which is analog in nature. These amplifiers are highly efficient and have an efficiency of about 90%. This is so because the output transistors used are fully turned on/off in a normal operating. Use of this approach eliminates the need to use the transistor’s linear region that brings in inefficiency in the other types of amplifiers. Figure 1.4 shows a basic class D amplifier and a possible waveform. Since this class of amplifier has a high efficiency.