Question

it's about an op amp question

Answer 1

It's a summing amplifier with the input at the inverting terminal. The output

\[Vout = - (\frac{ Rf }{ R1 } V1 + \frac{ Rf }{ R2 } V2 )\]

Here Rf=feedback resistance= 10K ohms
R1=R2=5K
V1 = 100mV ; V2= 200mV

Plug in the values.

Answer 2

what equation do i use?

Answer 3

i did something like I1+I2 = I3, then i got 100mV->0.1V and 200mV->0.2V. So 0.1/5K, 0.2/5K, then I add them together I3 = 0.3/5K. So given Rf=10K, I just multiply them together? I3 * Rf? because of the Vout = (Rf/Ri)* Vi?