My version of the G = 1000 low noise measurement amp (for Ikoflexer)

I recently went through this thread and may have missed the response, but the same question I had about the schematic was brought up by Samuel Groner (isn't Ccomp providing positive feedback?). Couldn't find an answer in the thread, just that it does seem to work without it.
 
I recently went through this thread and may have missed the response, but the same question I had about the schematic was brought up by Samuel Groner (isn't Ccomp providing positive feedback?). Couldn't find an answer in the thread, just that it does seem to work without it.

No, to get the DC leveling to work the first 1/2 of the 823 needs to be non-inverting for AC it's open-loop and the second 1/2 is simply an inverter so pin 3 looks like the minus input of a composite amp. It's not much of a composite so Ccomp is optional, I ALWAYS figure someone's (usually my) layout will oscillate. There are several low frequency time constants so be careful of motorboating/peaking at sub-HZ frequencies, you can sim the circuit by using CCCS's for the PV's, they do have a high frequency limit but that does not figure here.
 
Last edited:
Do you think that would qualify for a nice waterfront winter get away in SD? :) BTW I loved the area and winter climate.

Hahaha, not quite, but I'm sure your housing costs are similarly to ours here. :) I did bike up to campus this morning in just the same stuff I wear throughout the summer. It's ridiculous.

I'm actually going to be moving up to my home town (and close to one of your AD site) to take a postdoctoral position at OHSU. We think we're close to something worth going commercial and it'll need a bit more R&D incubation/collaboration. Fingers crossed!
 
minimal presence after retirement.

You still have to sign up for Medicare Part A. I've been on "minimal presence" for almost 20 years! It keeps everyone happy.

Getting back to the topic, I keep my IC's in drawers by manufacturer -- (still haven't combined Nat Semi and TI, however) -- I found some AD8512 which i will try out. A bit lower noise.