Basic
Electronics
Contents
S = Sound
TOC(Table
of Contents)
Chapt.1
Chapt.2
Chapt.3 S
Chapt.4 S
Chapt.5
Chapt.6A Chapt.6B
Chapt.7 S
Chapt.8
Chapt.9 S
Chapt.10
Chapt.11 S
Chapt.12 S
Chapt.13 S
Chapt. 14 S
Chapt. 15 S
Chapt. 16
Chapt. 17
Chapt.
18
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Back to Troubleshooting Workbook TOC
Active Filter Troubleshooting
The animation below shows the effect of varying C1 and C2 from .001 uf to .1uf on the frequency response of the Active Low Pass Filter. Use curve below for baseline information.
Troubleshoot Circuit Below
Determine the component failure which caused Fault 1 through Fault 3 shown by below plots. Select faulty component from list below. Hint: Do not give the same answer (1 - 6) twice.
1. C1 open
2. C2
decreased in capacitance(decrease less than 50%).
3. C1 Leaky.
4. C2 Leaky.
5. R1 open.
6. R2
open
ANSWERS AT BOTTOM OF PAGE
ANSWERS AT BOTTOM OF PAGE
ANSWERS AT BOTTOM OF PAGE
ANSWERS BELOW
Fault 1 Answer
No.2- C2 decreased in capacitance. (Failed C2 = .006uf )
ANSWERS BELOW
Fault 2 Answer
No.1- C1 Open
Note that with C1 open the circuit becomes a simple RC or first
order filter with an op-amp voltage follower. This results in
a reduced roll off rate of about 6db per octave
ANSWERS BELOW
Fault 3 Answer
No.4- C2 Leaky (Rparallel= 12k)
The voltage divider formed by Rparallel , R1, and R2 causes the normally unity low frequency gain of this circuit to be reduced.