I have a problem using LM741 for an non-inverting amplifier.
The schematic is attached.
A little explanaition :
The main problem is that i need to power the lm741s with a single 5 V power from the arduino. The second lm741 is the one who will amplificate the signal received from the sensor (here represented as a power supply).
The first lm741 instead it's configured as buffer, his job is putting the input pins of the lm741 at a 2,5 volt reference value, that is the reference of the second lm741.
Now the issues i have :
Depending on the gain I choose for the amplifier the lm741 will saturate at different voltages, for example
R_2 = R_1 -> gain = 2 -> high saturation voltage = 4,7 ; low saturation voltage = 0,9
R_2 = 10 * R_1 -> gain = 11 -> high saturation voltage = 4,2 ; low saturation voltage = 1,8
R_2 = 100 * R_1 -> gain = 101 -> high saturation voltage = 4 ; low saturation voltage = 3
So the saturation values change depending on the gain, note that in some case the reference value of the second lm741 (that should be 2,5 V) it's not included in the saturating range. This lead to the second issues, if instead of the sensor i put an external voltage supply, that provide 0,1 V i expect the lm741 to saturates high, and instead saturates low. I think it could be because the reference value of the second lm change as the saturation voltages do.
What could be the problem? Maybe the supply power i provide it's not sufficient?
here's the datasheet of my lm741: http://www.ti.com/product/ua741
(Pls note that the name of the op amps in the schematic is not matching the one im actually using)
Tell me if you need some more infos.
Thank you in advance.