ECE102
Quiz 2 – Question Pages
Winter 2007
1
Student ID
Name (Last, First)
Score
Question 1
(3 + 2 = 5 points):
Treat this opamp configuration as a feedback system. The op amp gain is
G
(and the op
amp is otherwise ideal).
(a)
Find the loop gain.
(b)
Find the feedback factor
β
.
Question 2
(2 + 2 + 2
+ 2 = 8 points):
The figure below shows the Bode plot of the open loop gain
A
of a feedback system. The
feedback factor
β
= 10
2
.
(a)
Find the magnitude (in dB) of the closed loop gain, 
A
f
, at
ω
= 10
3
.
(b)
Find the magnitude (in dB) of the closed loop gain, 
A
f
, at
ω
= 10
10
.
(c)
Find the magnitude (in dB) of the closed loop gain, 
A
f
, at
ω
= 10
11
.
(d)
Find the magnitude (in dB) of the closed loop gain, 
A
f
, at
ω
= 10
12
.
25
Write your answers on the separate answer pages; we will not look at these question pages.

A
 (dB)
ω
(log scale)
80
10
6
+20 dB/dec
10
10
40 dB/dec
40
10
8
10
12
10
4
10
2
120
v
IN
v
OUT
1 k
Ω

+
1 k
Ω
1 k
Ω
1 k
Ω
1 k
Ω
G
2 k
Ω
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document