In closed loop control system, with positive value of feedback gain the overall gain of the system will

In closed loop control system, with positive value of feedback gain the overall gain of the system will

Right Answer is: Increase

SOLUTION

In a closed-loop control system, with a positive value of feedback gain the overall gain of the system will increase.

Closed-Loop Control

• A closed-loop control system utilizes a measure of the actual output to compare the actual output with the desired output response.
• The measure of the output is called the feedback signal. The elements of a general closed-loop feedback control system are shown in Figure.

• A closed-loop control system compares the measurement of the output with the desired output (reference or command input).
• The difference between the two quantities (the error signal) is then used to drive the output closer to the reference input through the controller and actuator.
• Often the difference between the output of the process under control and the reference input is amplified and used to control the process so that the difference is continually reduced.

The transfer function of the closed-loop transfer function, with the positive value of feedback gain is given by

$\frac{{G\left( s \right)}}{{1 – G\left( s \right)H\left( s \right)}}$

• If the feedback signal enhances the magnitude of the input signal, the feedback is referred to as positive, direct, or regenerative feedback.
• The overall gain of the amplifier is increased by positive feedback.
• Regenerative feedback implies feedback with a Positive sign.

Positive feedback causes instability in the gain of the amplifier and distorts the input signal. It is used in narrowband amplifiers and radio receivers because it increases the signal strength.

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