Scenarios 1 and 2 below apply when the op-amp is either open-loop or closed-loop: -
- If the open-loop voltage gain is only 100 (for instance) then the voltage difference between the two op-amp inputs needs to be 10 mV to produce 1 volt at the output. 100 mV is needed to produce 10 volts at the output.
- If the open-loop voltage gain is 10,000 then the the voltage difference between the two op-amp inputs need only be 0.1 mV to produce 1 volt at the output. 1 mV is needed to produce 10 volts at the output.
In the second scenario, the difference between the op-amp inputs is mainly less than 1 mV and you would say that this is much more of a virtual earth/ground than the first scenario. And for many op-amps (at DC), the open-loop voltage gain is in the order of 100,000 to 1,000,000.
How does steady-state error from control theory tie into op-amps?
Increasing open-loop gain improves the error? I'm trying to make a
link between the two courses.
An op-amp is a control system and so it applies 100%.