- #1

Rushers

- 6

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In a control system, we have a substractor, forward path and feedback path.

The forward path is described by a function g ( a gain function ) and the feedback by another function ( gain again ).

The input is Xi and the output is Xo.

Let's suppose we are controlling the voltage so X is a voltage.

Our sensor in the feedback path reads the value of the voltage. This value is multiplied by B. My question is .Why?

If we want to substract from the reference value at the substractor, why would we multiply by a gain and modify the real value of voltage?

Then we substruct so we get (Xi -BXo) and then multiply by A to get A(Xi - BXo).

This new value is supposed to be the new value of voltage.

Xo = A(Xi -BXo) with TWO values of Xo. We have Xo previous and Xo after the operation of modification.

But in the textbook they say these values are the same and deduce a "gain" of the circuit (A/ (1 + AB)).

Why, if we have two values of Xo, are they taken to be similar?

AND what does this "gain" represent?