3-38
Eout = E2 - E1
Eout = (+12V) - (+3V)
Eout = +9V
To check this output, first compute the value of R2 plus R4:
With this value, compute the current through R2 (IR2):
(indicating current flow from left to right)
Next, compute the voltage drop across R2 (ER2):
Then compute the voltage at point B:
Since point B and point A will be at the same potential in an operational amplifier:
Now compute the voltage developed by R1 (ER1):
Compute the current through R1 (IR1):
