3-40
Then, for a difference amplifier:
With the same inputs that were used for the subtractor, (E1 = + 3 V; E2 = + 12 V) the output of the
difference amplifier should be five times the output of the subtractor (Eout = + 45 V).
Following the same steps used for the subtractor:
First compute the value of R2 plus R4:
With this value, compute the current through R2 (IR2):
Next, compute the voltage drop across R2 (ER2):
Then, compute the voltage at point B:
Since point A and point B will be at the same potential in an operational amplifier:
