U4 is the output of the circuit configured as a comparator, so the output will be either high or low.Nope--this is for a real world application (reading temperature). R10 in this circuit is actually an RTD. This circuit was designed by someone that is no longer working at my company--certainly not how I would have done it, but I have to live with it for now. I'm also terrible at analog electronics!
Perhaps the low end or R4 should be at –5V and not 0V (or even +5V)I can make little sense of that circuit.
As configured, U6's (+) input is always higher than its (-) input for any finite value of R10 so the output will always be high.
I think there's an error in the schematic.
Do you have a schematic of the original circuit, not the LTspice copy?
I don't see a U22.Clarification for above post: U4 in Spice circuit, but U22 in schematic picture
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