Introduction to Transistor Audio Power Amplifier
A practical amplifier always consists of a number of stages that amplify a weak signal until sufficient power is available to operate a loud-
speaker or other output device. The first few stages in this multistage amplifier have the function of only volt- age amplification. However, the last stage is
designed to provide maximum power. This final stage is known as power stage.
The term audio means the range of frequencies which our ears can hear. The range of human hearing extends from 20 Hz to 20 kHz.
Therefore, audio am- plifiers amplify electrical signals that have a frequency range corresponding to the range of human hearing i.e. 20 Hz to 20 kHz.
Fig. 12.1 shows the block diagram of an audio amplifier. The early stages build up the volt- age level of the signal while the last stage builds up power to a level
sufficient to operate the loudspeaker. In this chapter, we shall talk about the final stage in a multistage amplifier—the power amplifier.
A transistor amplifier which raises the power level of the signals that have audio frequency range is known as transistor audio power amplifier.
In general, the last stage of a multistage amplifier is the power stage. The power amplifier differs from all the previous stages in that here a concentrated effort
is made to obtain maximum output power.
A transistor that is suitable for power amplification is generally called a power transistor. It differs from other transistors
mostly in size ; it is considerably larger to provide for handling the great amount of power. Audio power amplifiers are used to deliver a large amount of power to a
low resistance load. Typical load values range from 300 (for transmission antennas) to 8 (for loudspeakers). Although these load values do not cover every possibility,
they do illustrate the fact that audio power amplifiers usually drive low-resistance loads. The typical power output rating of a power amplifier is 1W or more.
BASIC ELectronics be may 2018 DIPLOMA PAPER SOLUTION
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Zener Breakdown Region
Metal Oxide Filed Effect Transister
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What is Zener diode? Draw its symbol and characteristics
hybrid Parameter) of transistor
Temperature variations affect the operating point of a transistor
Phase reversal of output voltage with respect to input voltage in an Amplifier
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BASIC ELECTRONICS DIPLOMA MAY 2018 PAPER
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CE configuration of a Transistor Click Here