Does grid current flow in a grid-bias modulated stage under modulated conditions?

Does grid current flow in a grid-bias modulated stage under modulated conditions?

• A. It may exist during the positive portions of the AF cycle
• B. It may cause distortion
• C. Both A and B
• D. None of the above

Answer: (C)

In a grid-bias modulated stage under modulated conditions, grid current can indeed flow during the positive portions of the audio frequency (AF) cycle. This is primarily because modulation changes the signal's amplitude, which can lead to conditions where the grid becomes more positive than its equilibrium state, resulting in grid current flowing into the grid. Additionally, this grid current can introduce distortion in the output signal. When grid current flows, it can affect the biasing of the stage, altering the effective operating point and leading to nonlinearities in amplification, which manifest as distortion in the transmitted signal. Thus, both the presence of grid current during the positive portions of the AF cycle and the potential for distortion align with the situation described, making the combined option the correct response.

In a grid-bias modulated stage under modulated conditions, grid current can indeed flow during the positive portions of the audio frequency (AF) cycle. This is primarily because modulation changes the signal's amplitude, which can lead to conditions where the grid becomes more positive than its equilibrium state, resulting in grid current flowing into the grid.

Additionally, this grid current can introduce distortion in the output signal. When grid current flows, it can affect the biasing of the stage, altering the effective operating point and leading to nonlinearities in amplification, which manifest as distortion in the transmitted signal.

Thus, both the presence of grid current during the positive portions of the AF cycle and the potential for distortion align with the situation described, making the combined option the correct response.