Difference Amplifier

 Starting Lab....
In this lab, we are looking for a setup will take difeerence between two voltage source and either keep it as it was or multiply it as our output Voltage.

We did some calculation first to figure out what resistance we need to choose to achieve twice of difference of two voltage source (At end of calculation, I wrote R1=R2 but it can be ignored(wrong)), and we found out we need to choose a reisstor that will have relationship same as 2R_1=R_2, 2R_3=R_4.

We set it up(we did not take picture of circuit) and measured output Voltages.

We actually use negative of our result to plot and I will explain it in Summary.

We actually use negative of our result to plot and I will explain it in Summary.

Summary: So we did all that and measured output Voltage. Relationship of V_out and V_a and V_b is V_out=2(V_b-V_a), but we found out our result is negative of what we expected. So we figured out we must have our V_a and V_b swaped and cause negative output value. Than we have very similar expected and measured output Voltage.