Different behavior with same op amp with and without power supply

Just bought a license and was trying a simple circuit using an TL081 op amp.

I saw there are 2 options, one without power supply pins and other one with supply pins.

I tried both but the result is different.

Checking the negative input of the op amp I see it works different.

In the last image the amp- and amp+ are overlapped as expected.

Could someone explain why are not both signals equals in the "powered" op amp circuit?

Thanks,

by itzalak2
March 28, 2016

@itzalak2,

The links in your post are broken.

Please post a link to your schematic.

In the meanwhile, does this thread help?

https://www.circuitlab.com/forums/support/topic/p28xfm83/incorrect-simulation-of-an-opamp-under-positive-feedback/

by signality
March 28, 2016

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