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Using Arduino => General Electronics => Topic started by: tjones9163 on Aug 19, 2019, 01:33 am

Title: Power requirements for mic circuit
Post by: tjones9163 on Aug 19, 2019, 01:33 am
Hello, below I will have a picture of a condenser microphone circuit. The circuit works fine with 5v.
I am just wondering if it is safe to power with 9v battery?
I know the Lm386 can handle the voltage, I am just worried about the audio input jack!
Or is it not receiving power through the jack and just supplying the signal?
(https://forum.arduino.cc/index.php?action=dlattach;topic=632073.0;attach=320932)
Title: Re: Power requirements for mic circuit
Post by: SteveMann on Aug 19, 2019, 04:05 am
Google LM386 Datasheet.
The LM386N-1, -3, LM386M-1, LM386MM-1 are rated to operate between 4- to 12-Volts.
So, yes.

Title: Re: Power requirements for mic circuit
Post by: tjones9163 on Aug 19, 2019, 04:08 am
Google LM386 Datasheet.
The LM386N-1, -3, LM386M-1, LM386MM-1 are rated to operate between 4- to 12-Volts.
So, yes.


Thank you for the response, but i stated in my op that i know the lm386 can handle it, if you read above.
Is ok for my phone that is connected through the audio jack.
Title: Re: Power requirements for mic circuit
Post by: wolframore on Aug 19, 2019, 03:38 pm
Follow the signal flow for opamp.  Think this through... ask yourself...what happens at the input when there is no signal?  What happens at the input when the signal is high... I don't understand the connection to an Arduino.
Title: Re: Power requirements for mic circuit
Post by: DVDdoug on Aug 19, 2019, 04:37 pm
I assume you're connecting the phone's headphone-output?

Yes, it's signal-only.  You won't damage your phone.

That's a mono amplifier so you'll only get the left or right signal unless you build two (not great for music).   ...And, don't "short" the phone's left & right outputs together.


Quote
Hello, below I will have a picture of a condenser microphone circuit.
Hmmmm…..   There's no power for the condenser mic and the gain is too low for a microphone signal.


Title: Re: Power requirements for mic circuit
Post by: tjones9163 on Aug 20, 2019, 12:08 am
I assume you're connecting the phone's headphone-output?

Yes, it's signal-only.  You won't damage your phone.

That's a mono amplifier so you'll only get the left or right signal unless you build two (not great for music).   ...And, don't "short" the phone's left & right outputs together.

Hmmmm…..   There's no power for the condenser mic and the gain is too low for a microphone signal.



Im sorry below is the condensor mic circuit that i got confused with the last post.
Do you see anything wrong with this circuit?
(https://forum.arduino.cc/index.php?action=dlattach;topic=632073.0;attach=321074)
Title: Re: Power requirements for mic circuit
Post by: SteveMann on Aug 20, 2019, 08:34 pm
A condenser microphone normally needs a bias to operate because it has an FET pre-amp built in.  The voltage is not critical.  In professional sound systems, the mixer board will provide this bias in the form of "phantom power", typically 48-Volts.

A dynamic microphone generates power relative to the dynamic pressure of the sound striking it, and it needs no bias voltage.