Question #03d44

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Answer 1 · 2017-11-22T00:00:12

The answer is selection: a) 5

The general equation for a positive feedback system is:

#A_"c" = A_"ol"/(1 - betaA_"ol")" [1]"#

Where #A_"c"# is the closed loop gain, #A_"ol"# is open loop gain, and, #beta# is the gain of the feedback circuit.

We are given that #A_"c" = 10#

And the phrase; "10% positive feedback" implies that #beta = 0.1#

Substitute these values into equation [1] and solve for #A_"ol"#:

#10 = A_"ol"/(1- 0.1A_"ol")#

#10(1- 0.1A_"ol") = A_"ol"#

#10- A_"ol" = A_"ol"#

#2A_"ol"=10#

#A_"ol" = 5#

The answer is selection: a) 5