# What is the voltage at the inverting input terminal of an op-amp, with respect to ground?

I am currently writing a lab report for an introductory lab in electrical engineering on the subject of op-amps. One question that I'm stuck at is

With the op-amp operating in its linear regime, what voltage would you expect at the negative (inverting) input terminal, with respect to ground? How does this compare with your measurement of $$\V_n\$$?

I think the goal is to test the idealness of an inverting op-amp with the data that I have here: The op-amp circuit: simulate this circuit – Schematic created using CircuitLab

Supply voltages:
$$\V_{cc+}=15.664\$$ V
$$\V_{cc-}=-15.143\$$ V

I was taught that the golden rule of an ideal inverting op-amp is $$\V_n=V_p\$$. But what is $$\V_p\$$? It can't be the input voltage because of the golden rule. How do I answer those questions with the given data?

• Was there a schematic with the question? It would be very useful. Feb 8, 2020 at 22:27
• @Transistor Yes, I just added it. Feb 8, 2020 at 23:20
• "But what is Vp?" By inspection, voltage Vp--the voltage at the op amp's non-inverting input--is zero volts. (NB: Ground potential is zero volts, and the op amp's non-inverting input is connected directly to ground potential.) Feb 9, 2020 at 1:24