Impedance matching using lm324

[scarebyte]

Hi,

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?

Thanks.
Regards.

 

[FvM]

There are several points that don't work as shown, some possibly just drawing errors. As a fundamental point, LM324 can't drive a 8 ohm speaker. You'll want a low power audio amplifier like LM386 for this pupose.

 

[goldsmith]

Hi Scarebyte
I hope that you didn't connect your speaker to the LM354 directly ! ( because it can't handle enough current ) .
Best Wishes
Goldsmith

 

[scarebyte]

Well I connected directly to the opam, and there was distortion, sound unclear. So what is the correct way of connect the speaker?
Thanks.

- - - Updated - - -

I see, the current is too low. My supply voltage is 32Vdc , which opamp I should use?
Thanks.

 

[goldsmith]

Hi again
You can use a transistor circuit as buffer for high powers . for example a complementary stage . it would be ok . or a complementary stage with an op amp ( takes feed back from out put to do it's best as a buffer ! )
Best Wishes
Goldsmith