OP amp question. Calculate the gain vi/vo.

Not open for further replies.

Thread Starter


Joined Aug 20, 2019
Hi I'm currently stuck on current question.

Consider the following OP amp circuit in . Obtain the gain vo/vi of the amplifier.

View attachment 206776

What I can see is I can find the voltage on positive and negative pin of top OP amp, which is 30/50*vi (because positive pin of top OP amp is in parallel with 30 ohm resistor, in other words, they have same voltage and inverting and non-inverting pins of OP amplifier have same voltage.
Next, I can find the voltage of bottom OP amp, the same way, 80/120*vi or 20/30*vi.
After this I'm stuck ,as I don't know what to do. Two of the OP amps are connected together, but have different voltages. Is that mean that excess voltage (ie 20/30*vi - 30/50*vi) is at the 2k ohm resistor? I see that I require to use KVL in order to solve it, I just don't know from where to start
Not open for further replies.