Operational Amplifiers

1
12
Operational Amplifiers
2
Figure 12.2 A voltage amplifier
R
S


v
(
t
)
v
(
t
)
R
Gain,
A
_
S
L
L

Source
Amplifier
Load
3
Figure 12.3 Simple voltage amplifier model
R
R
out
S


Av
v
in
S


v
R
v
_
_
in
L
R
L
in


4
Figure 12.4 Operational amplifier model symbols,
and circuit diagram






IC op-amp diagram
5
Figure 12.5 Inverting amplifier
R
F
i
F
R

v
S

i
in
i

S



v
_
v
S
v
out

6
Figure 12.7 Summing amplifier
R
F
R
S
1
i
F

i
1
_
v
S
1
v
out
R
S
2

i
2
_
v
S
2
R
S
N

i
N
_
v
S
N
7
Figure 12.8 Noninverting amplifier
R
F
i
i
F
R
in
S

v

i
S
v



R
i
in
v

out
v
_
S

8
Figure 12.9 Voltage follower


i

in
v

out
v
_
in

9
Figure 12.10 Differential amplifier
R
2
i
2
R
1


i
1


v
v
out
R
_
1
1


v
R
_
2
2
10
Figure 12.14 Instrumentation amplifier
v
R
R
1
F
R
2
R
1
V
out
R
2
R
v
2
R
F
11
Figure 12.20 Op-amp circuits employing complex
impedances
Z
F
I
F
Z

S


I

S
V

out
V
S


Inverting
Z
F
I
F

Z
S

I

V
S
out


V

S

Noninverting
12
Figure 12.21 Active low-pass filter
Z
F
C
F
R
F
R
S




V
V
out
_
S

13
Figure 12.24 Active high-pass filter
R
F
Z
S
C
R
S
S



V
out

V
_

S
14
Figure 12.26 Active band-pass filter
R
F
C
F
C
R
S
S




V
V
_
out
S

15
Figure 12.27 Normalized response of active
band-pass filter