Hi w,
Thanks for the positive feedback.
You could construct a INA using those 3 OPA's.
E

 

You could construct a INA using those 3 OPA's.

Which, of course, has a lower common-mode rejection than an IC INA, unless highly matched resistor ratios are used.

 

Hi w,
If you want to salvage and repurpose those 3, OPA's you could make up up a simple INA circuit for testing your project.

If you are interested in in building a INA, I could post a basic circuit.

I am sure you are aware, that you will not get the performance by building your own INA, but it could be a useful learning exercise.

E

 

Hi w,
This is an option for trying out a INA with the 'fake' OPA's
E

 

Hi eric,

Thanks a lot, yes as you said ... I need a good performance, plus I need to use 3 or 4 AD620 , it would be so messy, plus I only have 5 fake AD620 X) ....
Appreciate your help

 

Hi w,
This is an option for trying out a INA with the 'fake' OPA's
E
View attachment 303117

Nice ... Would be cool to try it

 

Hi w,
OK, let's know how it goes, there have been a number of EMG threads on the forums.

E