反相放大器 简易运算放大器电路

1 +
R4 R2
+
R4 R3
1
MΩ
100
1MΩ
1MΩ υI
R1
R2 100MΩ υO
1MΩ υx 1MΩ
1MΩ υI
R1
R2
R4
R3 10.2kΩ
υO
98
G
= υO υI
= − R2 R1
1+
R4 R2
+
R4 R3
1
1
100
R3 =1MΩ/98=10.2kΩ
Current-to-Voltage Converter (CCVS)
Adυd
R2
υ1 R1 i
υd
υ2 i R1 R2
R2
υ1 R1 i1
υd
υc
υ2 i2 R1
R2
i1
=
i2
=
υc R1 + R2
υO
=
R2 R1
(υ2
−υ1 )
Virtual short circuit
Rd
= υd i
= 2R1
υO = 0
Rc
=
υc i1 + i2
=
R1 + R2 2
1. 2. 3.
G = υO = −
R2 / R1
υI 1+ (1+ R2 / R1) / A
Input port
Output port
Tinverting amplifier with a T
-network)
1 υI
2
i2
=
i1
=
υI R1
i2
i1
=
υI R1
υx
=
0 − υI R1
R2
=
−
R2 R1
υI
3
υx i4
υO
υO = −Rf i
=
Fra Baidu bibliotek−Rf
υ1 R1
+
υ2 R2
+L+
υn Rn
=
−
Rf R1
υ1
+
Rf R2
υ2
+L+
Rf Rn
υn
difference amplifier)
υ1 R1
υ2
R3
R2
υ2 =0υ
O1
υ1 =0υ
O2
υO
υO = υO1+ υO2
R4
υO
=
−
R2 R1
υ1
+ 1+ R2 / R1 1+ R3 / R4
inverting amplifier)
Virtual ground
i2
=
i1
=
υI R1
2
1
i1
=
υI R1
R2
υI
R1
i
− I
=0
iI+=0
υO
A
0V
3
υO
=
0 − υI R1
R2
=
−
R2 R1
υI
G = υO = − R2
υI
R1
Ri
= υI i1
= R1
R0 = 0
υI
R1
GυI υO
finite open-loop gain A
R2
R4
i4
=
i2
+
i3
=
υI R1
+
R2 R1R3
υI
R3
i3
i3
=
0 −υx R3
=
R2 R1R3
υ
I
4
R1
i
− I
=0
A
υO
5
iI+=0
0V
6
υO
=υx
− i4R4
=
−
R2 R1
υI
−
υI R1
+
R2 R1R3
υ
I
R4
G
= υO υI
= − R2 R1
−
R4 R1
1+
R2 R3
= −
R2 R1
υ2
υ1 R1
υ2
R3
R2
υO1
R4
υO1
=
−
R2 R1
υ1
Rin1 = R1
R2
υ1 R1 υ2 R3
υO2
R4
υO2
=
R4 R3 + R4
1+
R2 R1
υ2
Rin2 = R3 + R4
υO
=
−
R2 R1
υ1
+
1+ 1+
R2 R3
/ R1 / R4
υ2
υ
CM υ
d
υ1 = υ2 = υCM
υO
= −
iI=0 υI
υO =υI
υI
Ri
G=1 Ri→∞ Ro→0
1. 2. 3. 4.
υI
υO
180º
1
Weighted Summer (
υ1
R1 i1
i
υ2
R2
i2
Rn
υn
in
Summing amplifier
i = i1 + i2 +L + in
Rf
= υ1 + υ2 +L + υn
R1 R2
Rn
RF
iI
υO = −RFiI
υO
Transresistance Amplifier
iI(t)
RF iI υO
Voltage-to-Current Converter (VCCS)
υI R iI
iL
iL
= υI R
ZL
υO υO
Virtual ground
iI
iL
υI
υI
ZL
R
Voltage Follower (Buffer)
instrumentation amplifier) Rin = ∞
Rin = ∞
IC
R2 R1
+ 1+ R2 / R1 1+ R3 / R4
υCM
→
0
CMRR
0
⇒ R2 = R4 R1 R3
R R2=R4
1=R3
⇒ υO
=
−
R2 R1
υ1
+1+ 1+
R2 R1
/ /
R1 R2
υ
2
υO
=
R2 R1
(υ 2
−υ1 )
Ac=0A d= R2/R1
υ1 Rin1 = R1
υ2 Rin2 = R3 + R4