Say the input to the non-inverting terminal to this op-amp is 5 V, what is the voltage at the inverting terminal? I always assumed that the non-inverting and inverting terminals have the same voltage at all times but this is not reflected in simulation.
What is the correct answer here?
I guess the main question to ask is: why don't the terminals have the same voltage in an op-amp?
Best Answer
At all times? Nope. This is true if and only if there's a negative feedback. Without feedback the op amp can't equalise its inputs.
If you want the inverting input to be equal to the non-inverting input then tie the bottom end of that 1k resistor to output instead of ground:
simulate this circuit – Schematic created using CircuitLab
NOTE: Theoretically R1 can be anything but open (infinite resistance) as an op amp's inputs draw zero current. Shorting it will create an ideal buffer (a.k.a. follower).