Hello, I'm pretty confused with the comparator circuit I designed. The (-) reference voltage is set to 2.5V in order to digitize a (+) input voltage ranging from 0 to 4V. However, what I get at the output of the op-amp is somewhat equal to the (+) input voltage rather than a signal which switches between 0 to 5V. I'm quite sure there is nothing wrong with the comparator. I suspect the problem lies on the input voltage which is sourced from another op-amp. But I can't really figure out what the problem is. Can anyone help?

Question

ybarrap · Answer

This comparator 
|dw:1396224153911:dw|

Will produce this output
|dw:1396224359785:dw|

Make sure you don't have any feedback resistors in your loop from the output to the input.