LM324, LM324A, LM224, LM2902, LM2902V, NCV2902
50 k
R1
V
CC
R2
V
CC
-
V
ref
1/4
5.0 k
10 k
-
V
CC
1/4
MC1403
2.5 V
LM324
+
V
O
1
V
ref
= V
CC
2
R1
1+
R2
R
LM324
+
V
O
1
f
o
= 2
π
RC
C
For: f
o
= 1.0 kHz
R = 16 kΩ
C = 0.01
µF
V
O
= 2.5 V
C
R
Figure 10. Voltage Reference
Figure 11. Wien Bridge Oscillator
e
1
+
LM324
-
R1
a R1
b R1
-
V
ref
1/4
1/4
1
CR
R2
R
R1
V
OH
+
V
O
1/4
Hysteresis
LM324
+
1
CR
R
e
o
V
in
V
inL
=
V
inH
=
H=
LM324
-
V
O
V
OL
V
inL
V
ref
V
inH
-
e
2
LM324
+
1/4
R1
(V
OL
- V
ref
) + V
ref
R1 + R2
R1
(V
OH
- V
ref
) + V
ref
R1 + R2
R1
(V
OH
- V
OL
)
R1 + R2
e
o
= C (1 + a + b) (e
2
- e
1
)
Figure 12. High Impedance Differential Amplifier
Figure 13. Comparator with Hysteresis
R
R
V
in
C1
R2
-
C
R
C
-
1/4
100 k
1
f
o
= 2
π
RC
R1 = QR
R1
R2 =
T
BP
R3 = T
N R2
C1 = 10C
For: f
o
= 1.0 kHz
For:
Q = 10
For:
T
BP
= 1
For:
T
N
= 1
Notch Output
R
C
R1
R2
R3
= 160 kΩ
= 0.001
µF
= 1.6 MΩ
= 1.6 MΩ
= 1.6 MΩ
V
ref
=
1
V
2
CC
LM324
+
1/4
100 k
LM324
+
Vref
Bandpass
Output
-
R3
1/4
-
LM324
+
V
ref
C1
1/4
V
ref
R2
R1
LM324
+
V
ref
Where: T
BP
= Center Frequency Gain
Where:
T
N
= Passband Notch Gain
Figure 14. Bi–Quad Filter
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