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Old 4th September 2012, 06:01 PM   #1
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Default Impedance matching using lm324


I have an intercommunicator, that have an speaker/mic. I want to connect it in parallel and using an comutator, to a mic and speaker. For impedance fix I'm using an op-amp(lm324) in buffer configuration. I get notorious distortion, so I'm using a 6.8kohm connected to ground and out, that is ok?. The mic have 500ohm rate impedance output. The connections in the figure are ok?, how can improve?

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Old 4th September 2012, 07:10 PM   #2
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Is not quite correct, because the resistance of 6.8K will change output impedance.
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Old 4th September 2012, 08:11 PM   #3
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Originally Posted by donpetru View Post
Is not quite correct, because the resistance of 6.8K will change output impedance.
Ok, so what could be a good configuration?. And which opamp use if my supply voltage is 32Vdc?

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Old 4th September 2012, 09:28 PM   #4
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To be honest I do not quite understand what you are doing.
You cannot drive a speaker with the LM324 because it can sink and source too little current. You cannot amplify an AC signal with a single supply Opamp without a DC offset. The fact that the LM324 is a very poor audio amplifier will probably be your least problem. Why not make a more detailed/exact schematic? Then we can discuss in detail.
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