What class of amplifier is used as linear in order not to distort the modulation components?

• A. Class A
• B. Class B
• C. Class C
• D. None of the above

Answer: (B)

The correct choice emphasizes that Class A amplifiers are known for their ability to amplify signals linearly, which is essential for avoiding distortion of modulation components. Class A amplifiers operate by conducting over the entire range of the input signal. This continuous conduction ensures that the output mirrors the input signal without introducing non-linear distortions, making it ideal for applications where signal fidelity is crucial, such as in the modulation of radio frequencies.

Class B amplifiers, on the other hand, are designed to conduct for only half of the input signal cycle, which can lead to crossover distortion at the point where one transistor turns off and another turns on. This type of distortion is undesirable when preserving the integrity of modulation components is the goal.

Class C amplifiers are optimized for efficiency and are typically used in applications like RF transmission where distortion is less of a concern. They operate in a mode where conduction occurs for much less than half of the input cycle, further increasing distortion risks during modulation.

Understanding these amplifier classes highlights why Class A is the appropriate answer for maintaining linearity and avoiding distortion during signal amplification.