Engineering Projects

Maximum Collector Circuit Efficiency of Class A Amplifier Conversion Efficiency An amplifier draws a.c. power from dc supply (collector supply VCC in CE amplifier) and converts a part of it into useful a.c. power delivered to the load impedance. The ratio of the a.c. output power to the d.c. power from the supply source in the output is called the conversion efficiency, also called collector circuit efficiency in the case of CE amplifier and is denoted by Greek letter . Thus,           ……(1) For present analysis, we assume a resistance…

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Transformer Coupled Audio Power Amplifier: Untuned large signal amplifier (power amplifier) of class AB and B type invariably use transformer coupled stages while those of class A type also generally use transformer coupled stage. RC coupled stages are not used because the quiescent current flawing through the load resistor results in large wastage of dc power in it. This dc power dissipated in the load resistor does not contribute to the useful ac output power. Further flow of dc current through the output device is not desirable. Hence it is…

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Second Harmonic Distortion in Amplifier In the graphical analysis given in the preceding article, the amplifying device is assumed to be preferable linear. Thus, we have assumed the output characteristics to be linear, parallel and equi-spaced for equal increments of the parameter. Then the corresponding dynamic transfer characteristic is also linear. Thus, linear amplification requires dynamic transfer characteristic to be linear. In practice, however, the dynamic transfer characteristic is never truly linear. For optimum linearity of amplification using the available amplifying device, we operate over such small region of dynamic…

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Large Signal Amplifier | Power Amplifier: In a multistage amplifier, first stage or the input stage and the intermediate stage are usually small signal class A amplifier stage while the last stage (the output stage) or sometimes last two stage are large signal amplifier (power amplifier) stage. Small signal amplifier stages serve to amplify the weak input signal to a sufficient large value to drive the final stage. The output stage generally feeds a transducer such as CR Tube, a loud speaker, a servo-control motor etc.  the large signal amplifier…

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Figure 1 gives the basic circuit of a transformer coupled CE amplifier stage. In figure 1, a current source Is having shunt source resistance Rs drives the amplifier through a transformer TR1. Load resistance RL is fed from the collector output circuit through a transformer TR2. A transformer coupled CE amplifier finds following applications: As input stage of a multistage simplified and usually driven by a microphone. As output stage feeding the load impedance and As intermediate stage Transformer coupling permits impedance matching thereby resulting in greater power gain. The…

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