# What is the name of the current that creates the potential difference in an opamp?

Almost zero current is drawn by an opamp from its inputs (in theory), but still there must be tiny current causing the opamp to feel the voltage. What is the name of that sort of current in electrical engineering terminology?

• It is not the current that causes the voltage - it is the other way round. Theoretically an opamp could have truly zero input current in the steady state. Mar 27, 2017 at 15:43
• Please, stop propagating this fallacy of voltage causing current (or vice-versa). electronics.stackexchange.com/questions/201533/… Mar 27, 2017 at 17:07

It's called "input bias current", if you're referring to the current that flows into the input terminals. See this tutorial from Analog Devices, which discusses the current in great detail. It points out that the input bias current $I_B$ can vary from a tiny 60 fA to many μA depending on the device. (60 fA is one electron every 3 microseconds, which is impressively low.)
You could also be referring to the input offset current $I_{OS}$, which is the difference between the two input bias currents.