How does negative feedback mechanism and positive feedback differ?

Answer 1

A negative feedback will stabilize an amplifiers positive feed back will force the amplifier to either saturated state. this will hold true for a system too.

A more general answer follows.

1. Feedback: Getting information about what just happened and responding to it.

2. Negative Feedback: The response lessens the output.

3. Positive Feedback: The response increases the output.

Answer 2

In positive feedback, the system moves the variable further and further away from the set point of the variable. In negative feedback, the system moves the variable back to the set point.

Another answer

Negative feedback will stabilize an amplifier. Positive feedback will force an amplifier into an unstable state. This holds true for any other system too.

Another Answer

Negative feedback subtracts a portion of the output from the input signal. Positive feedback adds a portion of the output to the input. Both are useful. In an amplifier, negative feedback increases stability and bandwidth, but reduces gain. Positive feedback produces an oscillator.

Answer 3

Negative feedback occurs when the output of a system acts to oppose changes to the input of the system, with the result that the changes are attenuated. If the overall feedback of the system is negative, then the system will tend to be stable.

A system exhibiting positive feedback, in response to perturbation, acts to increase the magnitude of the perturbation. That is, "A produces more of B which in turn produces more of A".[1] In contrast, a system that responds to a perturbation in a way that reduces its effect is said to exhibit negative feedback. These concepts were first recognized as broadly applicable by Norbert Wiener in his 1948 work on cybernetics.[2]

Answer 4

Negative feedback mechanisms work to maintain homeostasis by reversing a change in a physiological parameter, bringing it back to its set point. In contrast, positive feedback mechanisms amplify a change in a physiological parameter, leading to a continued deviation away from the set point until a specific endpoint or outcome is achieved.