- #1
Mechatron
- 38
- 0
In the inverting operational amplifier circuit I've drawn below I am trying to calculate the output voltage and the voltage at the blue spot. The resistors are of the magnitude of several K ohm.
I have done the following:
Uout = Rf * (I1+I2+I3) = Rf * (U1/R1 + U2/R2 + U3/R3)
The voltage Ux before the negative input pin of the operational amplifier:
Ux - Uout = Rf * (I1+I2+I3)
Ux = Rf * (I1+I2+I3) + Uout
The circuit:
http://s8.postimg.org/s6yj53wcl/Circuit.png
I have done the following:
Uout = Rf * (I1+I2+I3) = Rf * (U1/R1 + U2/R2 + U3/R3)
The voltage Ux before the negative input pin of the operational amplifier:
Ux - Uout = Rf * (I1+I2+I3)
Ux = Rf * (I1+I2+I3) + Uout
The circuit:
http://s8.postimg.org/s6yj53wcl/Circuit.png