Introduction to Negative Feedback

Negative feedback is a technique commonly used in electrical circuits to regulate and stabilize the operation of a system. It involves taking a portion of the output signal and feeding it back to the input in an opposite phase, which helps to reduce the overall gain of the system.

Effect on Bandwidth

Negative feedback has a direct impact on the bandwidth of a system. Bandwidth refers to the range of frequencies over which a circuit or system can operate effectively. When negative feedback is introduced, it reduces the gain at higher frequencies, resulting in a decrease in bandwidth. Therefore, option 'a' is correct – the bandwidth will decrease as a result of introducing negative feedback.

Effect on Distortion

Distortion refers to any unwanted alteration or modification of a signal. In an amplifier circuit, distortion can occur when the output signal deviates from the input signal due to nonlinear behavior. Negative feedback helps to reduce distortion by correcting the errors in the output signal. It compares the input and output signals and adjusts the amplifier accordingly. Therefore, option 'c' is not correct – distortion will decrease as a result of introducing negative feedback.

Effect on Instability

Instability in a system refers to the tendency of the circuit or system to oscillate or become unpredictable. It is often caused by positive feedback, where a portion of the output signal is fed back to the input in the same phase. However, negative feedback helps to stabilize the system by reducing the overall gain and preventing oscillations. Therefore, option 'd' is not correct – instability will decrease as a result of introducing negative feedback.

Effect on Overall Gain

The overall gain of a system is the ratio of the output signal amplitude to the input signal amplitude. When negative feedback is introduced, it reduces the overall gain of the system. This is because a portion of the output signal is fed back to the input with an opposite phase, which counteracts the amplification effect. Therefore, option 'b' is correct – the overall gain will not decrease as a result of introducing negative feedback.