Defination and Classification of Power Amplifier

Definition of power amplifier

A transistor amplifier which raises the power level of the signals that have audio frequency range is known as transistor power amplifier. In general the last stage of multistage amplifier is the power stage. A power amplifier differs from the voltage amplifier. A transistor that is suitable for power amplification is generally called as power transistor.

Classification of Power Amplifier

The power amplifiers can be classified in the following ways.

1. According to the usage of Frequency Signals:

(i) Audio frequency power amplifiers.

(ii) Radio frequency power amplifiers.

(iii) Video frequency power amplifiers.

2. According to the period of Conduction:

(i) Class A Power Amplifiers: The period of conduction is for total 360 ^o(full cycle).

(ii) Class B Power Amplifiers: The period of conduction is for 180^o (half cycle).

(iii) Class AB Power Amplifiers: The period of conduction is greater than 180^obut less than 360^o (in between class A and class B).

(iv) Class C Power Amplifiers: The period of conduction is for less than 180^o.

3. According to the Configuration used:

(i) Single ended amplifier.

(ii) Push pull amplifier.

(iii) Complementary symmetry push pull amplifier.

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