What should the plate current do in the operation of a Class B audio amplifier?

• A. Fluctuate
• B. Remain Steady
• C. Increase
• D. None of the above

Answer: (A)

In the operation of a Class B audio amplifier, the plate current is expected to fluctuate. This is primarily because Class B amplifiers conduct during half of the input signal cycle—specifically, when the input signal is positive. As the audio signal varies, so too does the plate current, which responds to the amplitude of the signal. This characteristic is fundamental to Class B operation, allowing for efficient amplification of audio signals by utilizing the active conduction of transistors or tubes only during the necessary half of the waveform.

In contrast, if the plate current were to remain steady or increase continuously without fluctuation, it would suggest a different amplifier mode or indicate potential issues with the amplifier's operation. Therefore, recognizing that fluctuations in plate current are a normal and expected characteristic of Class B amplifiers helps to deepen understanding of amplifier design and functionality.