LM741 op-amp input

[darvaish]

what is minimum input voltage which LM741 op-amp can amplify when used as an amplifier

I tried to find this in datasheet but there is maximum value but not the minimum.May be its given in the form of some other parameter or i am unable to understand so plz help.

actually my pressure sensor MPXM2202AS can give me output proportional to input pressure in the range of 0 mV to 20 mV.This a differential output voltage.I want to use LM741 to amplify this output.

Any suggestion or consideration to be taken care of for this amplification

 

[williB]

if that was a national part they would have given ten different ways to hook it up..
**broken link removed**
since nothing will happen to either part by hooking it up to the inputs of the 741 .. connect the Vminus output to Vminus input.. and Vplus output to the Vplus input and see what happens..

 

[Russlk]

The minimum signal that an op amp can amplify is given by the noise spec, but the LM741 is old and does not have a noise spec. Try the TL071 Or TL072 which is a low noise amp. The application notes on this URL will have some helpful info for you: https://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPXM2202A&nodeId=01126990368710

 

[audioguru]

Opamps also have an input offset voltage spec. For most cheap opamps like 741 or TL071 it is a max of 6mV. Which means if the sensor gave a zero output voltage and the opamp has a gain of 1000, its output voltage will be anywhere from negaive 6V to positive 6V, each opamp would have a different voltage.

You can null the input offset voltage with a trimpot connected to the opamp, or just purchase a more expensive opamp that is laser-trimmed in the factory for low offset voltage.