E1C06 09/14/2010
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signal is sent directly to the inverting port. The output for such a circuit, using Equation 6.45, is
E o t
ð Þ ¼ A o E i t
ð Þ À E o t
ð Þ
ð
Þ
or writing in terms of the circuit gain, G ¼ E o t
ð Þ=E i t
ð Þ,
G ¼
A o
1 þ A o
% 1
ð6:49Þ
E i
E i
E i
E o
E i1
E i
E o
E i2
E i1
E o
E o
R 1
R 1
R 2
E o
R 1
R 1
R 2
R 1
R 2
R 2
R 2
R 1
R 1
E o
R 2
R 2
+
–
+
–
+
–
+
–
+
–
+
–
G =
R 1 + R 2
R 2
G =
R 2
R 1
E o
(E
=
i1 – E i2 )
R 2
R 1
(a) Noninverting amplifier
(c) Differential amplifier
(e) Integrator
(d) Voltage follower
(f ) Differentiator
(b) Inverting amplifier
A
C
C
G =
E i dt
–1
R 2 C ∫
E o = –R 2 CE i
⋅
R i
R s
Figure 6.20 Some common amplifier circuits using operational amplifiers.
6.6 Analog Signal Conditioning: Amplifiers 233