Explanation:

In a multistage RC coupled amplifier, the coupling capacitor (Cc) is used to couple the output of one stage to the input of the next stage. It is typically placed between the collector of the preceding stage and the base of the next stage in a common emitter configuration.

The coupling capacitor allows the AC signal to pass through while blocking the DC component. This is important because the DC component can cause biasing issues and can affect the operation of the subsequent stages. By blocking the DC component, the coupling capacitor ensures proper biasing and allows the AC signal to be amplified without any distortion.

Effect on Frequency Response:

The coupling capacitor has a significant effect on the frequency response of the amplifier. It acts as a high-pass filter, allowing high-frequency signals to pass through while attenuating low-frequency signals.

When a low-frequency signal is applied to the input of the amplifier, the coupling capacitor acts as an open circuit and blocks the signal from reaching the next stage. This limits the low-frequency response of the amplifier.

On the other hand, when a high-frequency signal is applied, the coupling capacitor acts as a short circuit and allows the signal to pass through to the next stage. This ensures that the high-frequency response of the amplifier is not affected.

Thus, the coupling capacitor limits the low-frequency response of the amplifier while allowing the high-frequency response to be amplified.

Importance of Low-Frequency Response:

The low-frequency response of an amplifier is important for accurately reproducing audio signals. It determines the ability of the amplifier to amplify low-frequency signals without distortion.

By limiting the low-frequency response, the coupling capacitor prevents any DC bias from affecting the subsequent stages. This ensures that the amplifier operates in the linear region and does not introduce any distortion to the low-frequency signals.

Conclusion:

In a multistage RC coupled amplifier, the coupling capacitor (Cc) limits the low-frequency response. It allows the AC signals to pass through while blocking the DC component, ensuring proper biasing and preventing distortion. The capacitor acts as a high-pass filter, allowing high-frequency signals to pass through while attenuating low-frequency signals.