Amateur ExtraE7G05
How can unwanted ringing and audio instability be prevented in an op-amp audio filter?
A
Answer
Practical circuits and system design
Type
A
Restrict both gain and Q
B
Restrict gain but increase Q
C
Restrict Q but increase gain
D
Increase both gain and Q
Answer Notes
Operational amplifiers used as active audio filters can become unstable if pushed too far. 'Ringing' (an unwanted oscillation that persists after a signal stops) and instability are often caused by configuring the circuit with too much gain and too high of a quality factor (Q).
To prevent these issues, both the gain and the Q must be restricted. A high Q means a very narrow bandwidth, which is highly prone to ringing when excited by transient audio signals. High gain can push the op-amp into non-linear operation or self-oscillation due to stray feedback.
Keeping both of these parameters within reasonable limits ensures stable audio performance. The distractors incorrectly suggest increasing one or both parameters, which would only exacerbate the instability.
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What is meant by the term “op-amp input offset voltage”?
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What is the gain-bandwidth of an operational amplifier?