Deriving Vout in an inverting operational amplifier.

[Sammyboss]

Pls does anyone know how to derive for Vout1 and Vout3 in terms of Va and Vb for an inverting operational amplifier. Thank you.

 

[Sammyboss]

this is an image about the question.

 

[Bob S]

Pls does anyone know how to derive for Vout1 and Vout3 in terms of Va and Vb for an inverting operational amplifier. Thank you.

See inverting amplifier section in http://physics.usask.ca/~angie/ep316/lab7/theory.htm

 

[yungman]

There is no Va and Vb! I see two input voltage. I only see Vin1 and Vin2. So you look at Vin1 and Vin2 contribute. Vout1 part due to Vin1 is -(R3/R1)Vin1. Vout1 due to Vin2 is -(R3/R2)Vin2 so the total Vout1:

V_{out1}=-\left[ \frac{R_3}{R_1}V_{in1}+\frac{R_3}{R_2}V_{in2} \right]

You try to do the next one.

 

[Sammyboss]

There is no Va and Vb! I see two input voltage. I only see Vin1 and Vin2. So you look at Vin1 and Vin2 contribute. Vout1 part due to Vin1 is -(R3/R1)Vin1. Vout1 due to Vin2 is -(R3/R2)Vin2 so the total Vout1:

V_{out1}=-\left[ \frac{R_3}{R_1}V_{in1}+\frac{R_3}{R_2}V_{in2} \right]

You try to do the next one.

Thanks a lot. that really helped