Mosaic
Well-Known Member
Folks I need some advice on making a difference amp to perhaps do a 20x amplification on a very low impedance (<1 ohm) voltage on the order of around 20mV to 200mV. The purpose is to read the voltage via a PIC 10bit ADC, using a LM4040 4.096v precision Vref shunt.
I have access to these opamps atm:
MCP 6001, LM258, MC33072, TLE2022, LM311, LM324 and LM239.![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
I think I can scale the precision Vref to 2.048 or less using a voltage divider switched by a logic FET via a uC pin for better sampling at the lower end of the scale. I have this logic level NFET:
https://www.electro-tech-online.com/custompdfs/2012/06/FDC6401N.pdf
At a glance the MCP6001 or the TLE2022 seem to have the best specs.
Since the input impedance is so low, would I be able to use a single op amp w/o input buffering such as in this tut?![Confused :confused: :confused:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
**broken link removed**
thanks!
I have access to these opamps atm:
MCP 6001, LM258, MC33072, TLE2022, LM311, LM324 and LM239.
I think I can scale the precision Vref to 2.048 or less using a voltage divider switched by a logic FET via a uC pin for better sampling at the lower end of the scale. I have this logic level NFET:
https://www.electro-tech-online.com/custompdfs/2012/06/FDC6401N.pdf
At a glance the MCP6001 or the TLE2022 seem to have the best specs.
Since the input impedance is so low, would I be able to use a single op amp w/o input buffering such as in this tut?
**broken link removed**
thanks!