Troubleshooting LM386 Amplifier Noise: Capacitor Value and Behavior Explained

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SUMMARY

The discussion focuses on troubleshooting noise issues in an LM386 amplifier circuit. Users confirmed that adding a 47uF capacitor at the output significantly reduces noise, while other capacitor values were ineffective. It was clarified that the LM386 is a power amplifier, not an operational amplifier, and proper usage requires consulting the datasheet from National Semiconductor. Additionally, implementing a Zobel network is recommended for optimal performance.

PREREQUISITES
  • Understanding of LM386 power amplifier functionality
  • Familiarity with capacitor values and their impact on circuit behavior
  • Knowledge of Zobel network design principles
  • Ability to read and interpret datasheets, specifically for LM386 from National Semiconductor
NEXT STEPS
  • Research the design and implementation of Zobel networks in amplifier circuits
  • Study the LM386 datasheet from National Semiconductor for detailed specifications
  • Explore the effects of different capacitor values on amplifier noise reduction
  • Learn about common troubleshooting techniques for audio amplifier circuits
USEFUL FOR

Electronics hobbyists, audio engineers, and anyone involved in DIY amplifier projects seeking to minimize noise in LM386 circuits.

miroku
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hi guys,
i'm doing the testing amplifier for my DIY project,
and i using LM386 IC, i found that is a lot of noise at the output.
i saw an example putting a capacitor at the output to reduce the noise, it work!
the value of capacitor is 47uF. it not work well for other value capacitor.
But i not sure why behaviors like that? help please...
 

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miroku said:
hi guys,
i'm doing the testing amplifier for my DIY project,
and i using LM386 IC, i found that is a lot of noise at the output.
i saw an example putting a capacitor at the output to reduce the noise, it work!
the value of capacitor is 47uF. it not work well for other value capacitor.
But i not sure why behaviors like that? help please...

The LM386 is not an opamp. It is a power amp, and you do not connect feedback around it like it was an opamp. Download the datasheet from National Semiconductor's website to see how it should be used.
 
Needs a zobell (spelling?) network.
 

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