E1C06 09/14/2010
11:55:7 Page 248
The static sensitivity (or gain) of the filter is given by K ¼ R 2 /R 1 . The filter retains the
Butterworth characteristics described by Equation 6.58a.
A first-order, inverting single-stage, high-pass Butterworth active filter is shown in
Figure 6.35b, using the 741 operational amplifier. The filter has a high-pass cutoff frequency of
f c ¼
1
2pR 1 C 1
ð6:67Þ
C 2
R 2
R 1
E 1 (t)
E o (t)
6
2
3
(a) Inverting low-pass filter
R 2
R 1
C 1
C 1
E 1 (t)
E o (t)
6
2
3
(b) Inverting high-pass filter
–
+
741
C 2
R 2
R 1
E 1
E o (t)
6
2
3
(c) Inverting bandpass filter
–
+
741
–
+
741
Figure 6.35 Common basic active filters. (a)
Inverting low pass. (b) Inverting high pass.
(c) Inverting bandpass.
248 Chapter 6 Analog Electrical Devices and Measurements
11:55:7 Page 248
The static sensitivity (or gain) of the filter is given by K ¼ R 2 /R 1 . The filter retains the
Butterworth characteristics described by Equation 6.58a.
A first-order, inverting single-stage, high-pass Butterworth active filter is shown in
Figure 6.35b, using the 741 operational amplifier. The filter has a high-pass cutoff frequency of
f c ¼
1
2pR 1 C 1
ð6:67Þ
C 2
R 2
R 1
E 1 (t)
E o (t)
6
2
3
(a) Inverting low-pass filter
R 2
R 1
C 1
C 1
E 1 (t)
E o (t)
6
2
3
(b) Inverting high-pass filter
–
+
741
C 2
R 2
R 1
E 1
E o (t)
6
2
3
(c) Inverting bandpass filter
–
+
741
–
+
741
Figure 6.35 Common basic active filters. (a)
Inverting low pass. (b) Inverting high pass.
(c) Inverting bandpass.
248 Chapter 6 Analog Electrical Devices and Measurements