# Open loop gain of non-inverting amplifier

How can I find open loop gain of this non inverting amplifier. I searched for answer but couldn't find the answer. Using formula Gain=1+R2/R1 I am not able to figure out values ofR2 and R1 – Big6
Mar 4, 2017 at 15:19

Redraw your amplifier as if it really had resistors per the standard diagram simulate this circuit – Schematic created using CircuitLab

Now plug the new values into your equation, and what do you get?

• R1=0, R2=infinity ,Gain=1+ infinity=infinity? Mar 4, 2017 at 15:31
• @FanBoy - Please refer my circuit to whatever you used for your gain equation. Do you see a difference? Like, in component numbering? Plus, your application of my numbers should have given not "1 plus infinity", but rather "1 plus infinity divided by zero", and that should be a clue that something is wrong and you should go back to your original equation. Mar 4, 2017 at 15:36
• Okay, but I'm not getting how R= infinity? How did you equate values of R? Mar 4, 2017 at 15:41
• Since R2 has disappeared from the diagram, no current can flow through it. Please apply Ohm's Law to a resistor, and find the resistance needed to produce no current. Since the output is connected to the + input, there is no voltage difference. Please apply Ohm's Law to a resistor, and find the resistance needed to produce no voltage. Mar 4, 2017 at 15:43

One way,directly we can say that output voltage is Vin,as for op-amp voltage at inverting & non-inverting op-amp should be same.