Operational Amplifier Fundamentals Unit 6 – The Noninverting Summing Amplifier
Exercise 2 – Summing and Averaging Operation
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to configure a noninverting amplifier as
a voltage averaging or summing circuit. You will verify your results with a multimeter.
EXERCISE DISCUSSION
- In a two-input noninverting summing amplifier, V1 and V2 are combined at VA because of
the high input impedance of the op amp. - If the circuit is in the voltage follower configuration, the gain is 1.
- If R1 equals R2, then VA equals (V1 + V2)/2.
- If R1 and R2 are not equal, then VA is determined by measurement or by application of the
superposition theorem. - If the input resistors are equal in value, any number of circuit input voltages can be averaged.
- VO equals the algebraic sum of the input voltages divided by the number of input voltages.