james007on wrote on Apr 3rd, 2011, 7:39pm:R1 = Rinput = 5.1K
R2 = Rfeedback = 500Kpotentiometer
Input is coupled with a small capacitor.
Also my circuit is very similar to that found in the Texas Instrument Application Note SLOA058- November 2000. Page 6 i believe and I have also created the VCC/2 buffer mentioned on more previous pages within the same application note.
Thank you for your response.
You should link to the article. It is
http://focus.ti.com/lit/an/sloa058/sloa058.pdfI assume you are using the circuit on the top. The circuit is fine so you either didn't hook it up properly or one of the components is not working or sized properly. Are your opamp supplies hooked up correctly? Are the inputs to the correct pins? Check the DC biases at the opamp output and input and see if they make sense. Find the ones that don't make sense, find out why they don't make sense, and fix them
![Grin Grin](https://designers-guide.org/forum/Templates/Forum/default/grin.gif)
. I'm not trying to sound snarky, but you really need to learn how to do this. Your professors probably aren't too busy... this is something you need to figure out on your own -- and I bet you will remember where you screwed up! My favorite was when I didn't have the scope connected up.... I sure did have low noise, however.
rg