its gotta go here

[Thunderchild]

well I'm trying to just setup a simple window comparator in multisim but oops... I discovered a second nature to the TL082.... its increased the voltage.... have I solved the planets power issues before even getting my solar panels up ??????

 

[Hero999]

There's also the phase inversion problem, the output flips when the inputs are operated too close to the negative rail.

I wouldn't recommend the TL8x/7x for this, use a real comparator like the LM393.

 

[Thunderchild]

yea well just for getting the idea down on erm... screen I wanted the op amps as they can source as well sink making it easier on me fidling around, i think there is something wrong with the TL082 model

 

[Hero999]

I'm not sure that's the case, your modle is probably working correctly. There are plenty of resources describing the phase inversion issue with the TL082.

TL082 phase inversion - Google Search

I'm sure you can get comparators that have a push-pull output so you don't need any pull-ups. There are also other op-amps you can use, i.e. LM358, LM1558 which don't suffer from phase inversion.