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What is a class AB amplifier used for?
The basic purpose of a Class AB amplifier is to preserve the basic Class B configuration while at the same time improving its linearity by biasing each switching transistor slightly above threshold.
How does a class B amplifier work?
Class B amplifier is a type of power amplifier where the active device (transistor) conducts only for one half cycle of the input signal. Since the active device is switched off for half the input cycle, the active device dissipates less power and hence the efficiency is improved. …
Which amplifier has highest distortion?
Class C amplifier
A Class C amplifier is biassed so that it conducts over much less than half a cycle. This gives rise to very high levels of distortion, but also it enables very high efficiency levels to be achieved.
Which is the main disadvantage of Class B amplifier?
The Class B amplifier circuit above uses complimentary transistors for each half of the waveform and while Class B amplifiers have a much high gain than the Class A types, one of the main disadvantages of class B type push-pull amplifiers is that they suffer from an effect known commonly as Crossover Distortion.
What makes an amplifier a class AB amplifier?
If the class AB operating point is closer to the class A operating point (resp. class B) than the class B operating point (resp. class A) the circuit will behave more such as a class A amplifier (resp. class B) by presenting a higher linearity but a lower efficiency (resp. higher efficiency but lower linearity).
Why do class AB amplifiers have PNP transistors?
We can note that a small portion of the signal is conducted simultaneously by the NPN and the PNP transistors. This ensures that no crossover distortion is observed during the amplification performed by class AB amplifiers.
Which is the most common class of amplifier?
There are very many more amplifier operational classes available to the designer these days. Modern silicon technology has opened up many more doors, but despite this, the basic three amplifier classes of class, Class B, and Class C, with the derivative Class AB which is a cross between Class A and B are still the most widely used.
Why are class AB amplifiers cannot be used in push pull configuration?
The main reason why this configuration cannot be used for class AB amplifiers is that the set of values of the resistors will only work for a particular push-pull configuration. Moreover, the set of values needs to be chosen very carefully, specially if the complementary transistors are different.