WEBENCH® Tools/LMC6482: Trying to design a turbidity sensor

Prudhvi Sagar

Part Number: LMC6482

Tool/software: WEBENCH® Design Tools

Hello,

I have designed a non inverting amplifier LMC6482. I am getting good gain when I use lower resistors for Rf and Rg (example 450 and 150 ohms I get gain of 4) but when I use resistors in range of kilo and mega ohms I get very low gain infact for mega I get less than 1 gain. How is this happening?

Regards,

Prudhvi Sagar

over 7 years ago

0 Prudhvi Sagar over 7 years ago

Genius 3785 points

I am trying to connect a photo diode to + and - of opamp. www.farnell.com/.../1672046.pdf. 203 FA

0 Thomas Kuehl over 7 years ago

TI__Guru* 93105 points

Hello Prudhvi,

It would be helpful if you could provide your full LMC6482 schematic and supply information.

What are the characteristics of the input signal in terms of waveform, amplitude and frequency? How is the output signal being measured when the correct and lowered gain conditions are obderved?

You mention a photodiode at the input, how is it being connected in the op amp circuit?

Regards, Thomas
Precision Amplifiers Applications Engineering

0 Prudhvi Sagar over 7 years ago in reply to Thomas Kuehl

Genius 3785 points

Hello,

I'm just checking with a function generator connected to + and - of opamp. Frequency is upto 1kHz and amolitude upto 1v. V+ I give as.5V and V- is 0.

Regards,

Prudhvi Sagar

0 Thomas Kuehl over 7 years ago in reply to Prudhvi Sagar

TI__Guru* 93105 points

Hi Prudhvi,

Please provide the requested schematic showing how you have the supplies and input source connect to the LMC6482 amplifier circuit.

Thanks, Thomas

Precision Amplifiers Applications Engineering

0 Dennis Goeke over 7 years ago in reply to Thomas Kuehl

TI__Genius 11135 points

Prudhvi

We haven't heard back from you so we assume you were able to resolve your issue. If not, post another reply below.

Thanks
Dennis

Amplifiers

Amplifiers forum

WEBENCH® Tools/LMC6482: Trying to design a turbidity sensor