LM2902W
Typical single-supply applications
Figure 24. High input Z, DC differential amplifier
Figure 25. Low drift peak detector
R1
100 kΩ
+V1
+V2
R2
100 kΩ
1/4
LM2902
R3
100 kΩ
eo = [ 1 +
R4
R3
]
(e2
-
e1)
As shown eo = (e2 - e1)
R4
100 kΩ
1/4
LM2902
IB
1/4
1/4
I B LM2902
eo
LM2902
eI
C
1 μF *
2I B
Zo
ZI
2N 929 0.001 μF
Vo
2IB
IB
R
1 MΩ
3R
3 MΩ
IB
1/4
LM2902
Input current
compensation
* Polycarbonate or polyethylene
Figure 26. Using symmetrical amplifiers to
reduce input current (general concept)
1/4
II
I B LM2902
eo
eI
IB
2N 929
IB
1.5 MΩ
0.001 μF
IB
3 MΩ
IB
1/4
LM2902
Aux. amplifier for input
current compensation
DocID9922 Rev 9
11/18
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