Class D power amplifier

Class D power amplifier. Class D power amplifier is a type of audio amplifier were the power handling devices are operated as binary switches. Since the power handling devices (MOSFETS) works as perfect binary switches, no time is wasted in between the transition of stages and no power is wasted in the zero input condition. Class D power amplifiers are much power efficient when compared to its predecessors like Class A, Class B and Class AB. Out of the list the most efficient Class AB only have a maximum theoretical efficiency of 78.5%. In practical scenario with real speakers as…

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Class C power amplifier

Class C power amplifier. Class C power amplifier is a type of amplifier where the active element (transistor) conduct for less than one half cycle of the input signal. Less than one half cycle means the conduction angle is less than 180° and its typical value is 80° to 120°. The reduced conduction angle improves the efficiency to a great extend but causes a lot of distortion. Theoretical maximum efficiency of a Class C amplifier is around 90%. Due to the huge amounts of distortion, the Class C configurations are not used in audio applications. The most common application of…

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Class AB power amplifiers

  In class AB power amplifiers, the biasing circuit is so adjusted that the operating point Q lies near the cut-off voltage. During a small portion of negative half cycle and for complete positive half cycle of the signal, the input circuit remains forward biased-and hence collector current flows. But during a small portion (less than half cycle) of the negative cycle”‘ the input circuit is reverse biased and, therefore, no collector current flows during this period. Class AB operation needs a push-pull connection to achieve a full output cycle.

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Harmonic distortion in power amplifiers

Harmonic distortion in power amplifiers. Distortion is a serious problem faced in power amplifier design. In faithful amplification the output signal must be a scaled replica of the input signal and if there is any dissimilarity between the input and output waveform, then the output is said to be distorted. Unpleasant sound output coming from an audio system, which is no more the faithful reproduction of the original audio is mainly due to distortion. Other reasons for bad sound output are noise, clipping etc and they are not discussed here. The figure given below shows faithful amplification and distorted amplification….

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Class B power amplifier

Class B power amplifier. Class B amplifier is a type of power amplifier where the active device (transistor) conducts only for one half cycle of the input signal. That means the conduction angle is 180° for a Class B amplifier. Since the active device is switched off for half the input cycle, the active device dissipates less power and hence the efficiency is improved. Theoretical maximum efficiency of Class B power amplifier is 78.5%. The schematic of a single ended Class B amplifier and input , output waveforms are shown in the figure below. From the above circuit it is…

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Class A Power Amplifier – Tutorial with Design and Theory

Class A power amplifier. Class A power amplifier is a type of power amplifier where the output transistor is ON full time and the output current flows for the entire cycle of the input wave form. Class A power amplifier is the simplest of all power amplifier configurations. They have high fidelity and are totally immune to crossover distortion. Even though the class A power amplifier have a handful of good feature, they are not the prime choice because of their poor efficiency. Since the active elements (transistors) are forward biased full time, some current will flow through them even…

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Practical Power Amplifier Stages and Block Diagram

Practical power amplifier. Audio power amplifier is an amplifier which produces amplification of power between the input and output. Theoretically every audio amplifier produces some amount of power amplification, but in practical scenario every audio amplifier cannot be called a power amplifier. It is the amount of power amplification that makes an amplifier power amplifier or not. A power amplifier must produce a considerable amount of power amplification so as to drive a load. Generally there is no fixed criteria for the output of a power amplifier even though some designers say 50W RMS, some 20W RMS and some other…

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Power Amplifiers and various types

Introduction To Power Amplifiers An amplifier system consists of signal pick-up transducer, followed by a small signal amplifier(s), a large signal amplifier and an output transducer. A transducer is used to convert one form of energy into another type. For example a microphone is used to convert acoustical energy into electrical energy. Conversely, a loudspeaker is used to convert electrical energy into acoustical energy. A motor is a transducer that is used to convert electrical energy into mechanical energy. The input transducer produces small electrical (typically voltage) signal, that needs sufficient amplification to operate some output device such as a…

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Power Amplifier Circuit using TDA2009

Power Amplifier Circuit – 25 Watts Description Here is the diagram of a 25 Watt power amplifier circuit made of  TDA 2009 IC.TDA 2009 has two channels each rating 12.5 watts on 4 Ohm load.Here the two channels are bridged to get a single out put channel weighting 25 W. TDA 2009 IC has also built in features such as short circuit protection,thermal protection, overload protection etc using very low external components.The most interesting factor I see about this IC is that it require no dual supply. Power Amplifier Circuit Diagram and Power Supply Circuit Schematic   Notes Do not…

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