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I'm simulating the following circuit of the 741 operational amplifier with BJTs:

741 operational amplifier with BJTs

I've configured my circuit to be a non-inverting fashion, so in theory the gain would be -Rf/Ri. However, no matter what I set my values of Rf and Ri to, my output voltage remains constant.

Here is an image of SPICE simulation, with the output voltage boxed in blue, the Rf boxed in green, and the Ri boxed in pink:

SPICE simulation

Does anybody see what's wrong with my circuit? And why my output voltage is always -4.81 V no matter what the values of Rf and Ri are?

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You seem to have at least one short. Orcad's schematic editor has the delightful habit of adding shorts here and there, perhaps there are others.

enter image description here

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    \$\begingroup\$ Yikes, didn't even notice that happen. Wasn't supposed to be a connection there. Thanks for pointing that out - probably my issue is in a few of those short circuits. \$\endgroup\$
    – Zashiony
    Commented Apr 5, 2021 at 4:15
  • \$\begingroup\$ That's a good catch! \$\endgroup\$
    – jonk
    Commented Apr 5, 2021 at 4:16

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