Which class of amplifier conducts for 180 degrees of the input wave?

The correct answer is Class B amplifier, which conducts for 180 degrees of the input wave. In a Class B amplifier, each transistor in the push-pull configuration conducts for one half (or 180 degrees) of the input signal cycle. This means that one transistor amplifies the positive half of the waveform while the other amplifies the negative half.

This design enhances efficiency compared to Class A amplifiers, which conduct for the entire 360 degrees of the input wave, resulting in higher power losses due to constant current flow. On the other hand, Class B amplifiers are generally more efficient because they do not conduct during the entire input cycle and therefore do not dissipate as much heat. Class C amplifiers, in contrast, conduct for less than 180 degrees and are primarily used in applications like RF transmission due to their high efficiency but are not suitable for audio applications. Class D amplifiers, also known as switching amplifiers, use a completely different approach and are known for their very high efficiency by rapidly switching on and off.

Overall, the defining characteristic of the Class B amplifier is its 180-degree conduction, making it suitable for specific applications where efficiency and linearity are balanced.