3-41Now compute the voltage developed by R1 (E_{R1}):Compute the current through R1 (I_{R1}):Compute the voltage developed by R3 (E_{R3}):Add this voltage to the voltage at point A to compute the output voltage (E_{out}):This was the output desired, so the circuit works as a difference amplifier.Q-28.What is the difference between a summing amplifier and an adder circuit?Q-29.Can a summing amplifier have more than two inputs?Q-30.What is a scaling amplifier?Refer to figure 3-27 in answering Q31 through Q33.