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Author Topic: Strange problem with Op-amp  (Read 336 times)
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I have tried to connect a microphone to arduino's analog input thought op-amp (LM741), I used the following circuit (image attached). The problem is that I get always the same value 840. I tried to replace the mic with DC motor and rotate it, but same problem ( i got value of 240 ). I'm not sure that there is a problem with the chip, I tested it as voltage follower and it worked perfectly.

What have I done wrong?


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Shannon Member
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The LM741 uses +/-15V split supplies.  It doesn't work at all with a 5V single rail supply.
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Also that circuit can't possibly work as even the most advanced opamp can't take its output voltage below the negative supply rail.
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Also that circuit can't possibly work as even the most advanced opamp can't take its output voltage below the negative supply rail.

yes, i know i just want to detect noise.

Thanks, I switched to LM324, it solved the problem.
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