input offset voltage?

[me0414013]

why some times we get negative input offset voltage and sometimes positive?

 

[chuckey]

Its because of the tolerances of the input transistors, multiplied by the opamps gain. i.e. a miss match of a millivolts might be on either of the two input transistors.
Frank

 

[me0414013]

thanks for ur xplaination....

 

[prestonee]

But offset of an amp shouldnt change polarity under the same circumstances if reapplied multiple times