FET amplifier for transducer

[John Ross]

Hi.

I'm looking to make a very small amplifier for a sound transducer. The
transducer output is in the uV range. Only have single supply (9V
available).

I'm looking to add gain between 100-500, maybe controllable with a
POT.

Any suggestions on making such an amplifier from FETs or discreet
parts? I'm trying to keep the cost low.

Ideally, I'd like to integrate a low-pass and high-pass to shape the
frequency response.

Thank you.
J.

 

[Winfield Hill]

John Ross wrote...

I'm looking to make a very small amplifier for a sound transducer.
The transducer output is in the uV range. Only have single supply
(9V available).

I'm looking to add gain between 100-500, maybe controllable with a
POT.

Any suggestions on making such an amplifier from FETs or discreet
parts? I'm trying to keep the cost low.

Why? Some mass production?

Ideally, I'd like to integrate a low-pass and high-pass to shape
the frequency response.

What kind of sound transducer?


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Thanks,
- Win

 

[Joerg]

Hello John,

I'm looking to make a very small amplifier for a sound transducer. The
transducer output is in the uV range. Only have single supply (9V
available).

I'm looking to add gain between 100-500, maybe controllable with a
POT.

Any suggestions on making such an amplifier from FETs or discreet
parts? I'm trying to keep the cost low.

Assuming with "sound" you mean something below 25kHZ why do you want to
do it discrete? Any old opamp should be able to do that. The LM324 costs
less than 20c at reasonable qties and you get four amps for that money.
It works nicely from 9V. Ok, it's not a FET input but after all you
would have to bias a FET with resistors anyway.

Regards, Joerg

http://www.analogconsultants.com

 

[Ken Smith]

In article <kkd2g11mc3bds6qatgpss8ue90brp951sv@4ax.com>,
John Ross <jros@msnn.com> wrote:

Hi.

I'm looking to make a very small amplifier for a sound transducer. The
transducer output is in the uV range. Only have single supply (9V
available).

I'm looking to add gain between 100-500, maybe controllable with a
POT.

Any suggestions on making such an amplifier from FETs or discreet
parts? I'm trying to keep the cost low.

If you are after 100-500 as a gain and filtering and a low cost, chances
are an op-amp will be cheaper than doing it with discrete parts.


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kensmith@rahul.net forging knowledge