SUB; ANALOG ELECTRONICS

PREPARED BY

MR.HUTESH BAVISKAR

PARUL POLYTECHNIC INSTITUTE

TYPE OF CALSS A POWER AMPLIFIER• There are two types in class A power amplifier

1) series fed class A power amplifier

2) class A power amplifier with transformer coupled load.

Sub: EDC -2 Topic: Class A Power Amplilfier

SERIES FED CALSS A POWER AMPLIFIER

Sub: EDC -2 Topic: Class A Power Amplilfier

Sub: EDC -2 Topic: Class A Power Amplilfier

• In circuit of series fed class A amplifier fixed bias is used with the help of resistance RB connected between + VCC supply and base.

• Load resistance is RC. Q is an NPN type power transistor used with heat sink.

• Input signal vs is coupled to the base through coupling capacitor cc . Here a source vs is shown but in practice the signal comes from the previous voltage amplifier stage.Sub: EDC -2 Topic: Class A Power Amplilfier

• When no signal is applied certain base current IB flows due to the fixed bias. So certain collector current ICQ flows so some VCEQ voltage is available.

• The value of the base resistance is selected such that the Q point is at the middle of the active region.

• When the input signal is applied the base current and so the collector current changes and the operating point shifts on the load line from Q to Q1 to Q to Q2 and back to Q.

Sub: EDC -2 Topic: Class A Power Amplilfier

OPERATION OF CLASS A POWER AMPLIFIER

Sub: EDC -2 Topic: Class A Power Amplilfier

Sub: EDC -2 Topic: Class A Power Amplilfier

THANK YOU

Sub: EDC -2 Topic: Class A Power Amplilfier