LM324, LM324A, LM324E, LM224, LM2902, LM2902E, LM2902V, NCV2902

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9

2

1

For less than 10% error from operational amplifier,

If source impedance varies, filter may be preceded with

voltage follower buffer to stabilize filter parameters.

where fo and BW are expressed in Hz.

Qo fo

BW

< 0.1

Given:fo =center frequency

A(fo)=gain at center frequency

Choose value fo, C

Then:

R3 =

Q

p fo C

R3

R1 =

2 A(fo)

R1 R3

4Q2 R1 - R3

R2 =

+

-

+

-

Vref =VCC

Vref

f =

R1 + RC

4 CRf R1

R3 =

R2 R1

R2 + R1

R2

300 k

75 k

R3

R1

100 k

C

Triangle Wave

Output

Square

Wave

Output

Vin

Rf

if

Vref

1/4

LM324

1/4

LM324

Figure 16. Function Generator

Figure 17. Multiple Feedback Bandpass Filter

Vref =VCC

1

2

-

+

VCC

R3

R1

R2

Vref

C

C

VO

CO = 10 C

CO

1/4

LM324