# Feedback

Discussion in 'Homework Help' started by aspirine, Oct 26, 2004.

1. ### aspirine Thread Starter New Member

Oct 26, 2004
5
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well ,

i am really confused what is feedback and

what's its function ?

2. ### semiconductor New Member

Oct 16, 2003
8
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Dont worry it should be all right;

just keep reading though the text books

(just kidding)

anyway you keep going and going and asking and asking since it is the right way to learn, hence get mad

3. ### mozikluv AAC Fanatic!

Jan 22, 2004
1,437
1
hi

i will just give a birds eyeview on this topic.

feedback is a process in which the output signal is sampled and fedback to the input to form an error signal that drives the amplifier. now depending on the type of feedback (negative or positive) there are 3 variables to consider, voltage, current and output which is symbolize as (x, y, & z). at the summing junction at the input, substract the feedback signal by so much to input signal to form the error signal represented by the formula (z = x + by) resulting to what we call gain.

generally gain is a phasor function of frequency which leads to stability problem in feedback amps. when frequency is increased gain will have to decrease because these no such amplifier that has infinite bandwith. now as gain decreases phase shift occurs

we can mainly categorize feedback as either positive or negative and are connected in 4 different ways such as (series shunt, shunt shunt, series series and shunt series).

the analysis of a feedback amps is presented by Mason signal flow graph.

pls. dont ask for more explanation becasue all this what i have cited can be found in electronic books.

4. ### avionicsgirl New Member

Oct 30, 2004
7
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negative feedback is all i have learned about thus far.

usually there are two resistors in a negative feedback loop.
you adjust those to determine how much feedback you would like to send to the negative terminal.

we send signals back to the amplifier from the output to limit the gain of the amplifier and sometimes eliminate unwanted components of a signal.