13-11-2012, 10:51 AM
SEMINAR REPORT ON POWER AMPLIFIER
POWER AMPLIFIER.pptx (Size: 509.64 KB / Downloads: 44)
INTRODUCTION
An amplifier receives a signal from some pick up transducer or other input source and provides a large version of the signal to some output devices or to another amplifier stages .
Definitions
In small-signal amplifiers the main factors are:
Amplification
Linearity
Gain
Since large-signal, or power amplifiers handle relatively large voltage signals and current levels, the main factors are:
Efficiency
Maximum power capability
Impedance matching to the output device
Amplifier Types
Class A
The amplifier conducts through the full 360 of the input. The
Q-point is set near the middle of the load line.
Class B
The amplifier conducts through 180 of the input. The Q-point is set at the cutoff point.
Class AB
This is a compromise between the class A and B amplifiers.
The amplifier conducts somewhere between 180 and 360
The Q-point is located between the mid-point and cut off.
Conclusion
We have gone through various term related to the Power Amplifier. The basic function of the Power Amplifier is similar to that of the amplifier. There are modification of Class A, Class B, Class AB, Class C and Class D Amplifier that increase power Efficiency. Output stages are classified according to the transistor conduction angle .
The lower the amount of conduction angle of the amplifier the higher the efficiency.