op amp summer (adder) circuit

This is a super short video on the functional use of an op amp inverting summer (adder) circuit. More detailed info is available at www.ece.utah.edu/~ece1250

>> In this video, I would like to review what a non-inverting summer does.

We begin by starting with a non-inverting amplifier that you see here,

where you have a single input voltage going to a single output voltage.

Then, we're just going to start adding input voltages to it.

So, we've got this Rs2 with a second voltage Vs2.

What happens over here is that this side acts somewhat like a voltage divider,

and so we're going to have an additional gain term over here which is

Rs2 over Rs2 plus Rs1,

and then we're going to add in our second voltage Vs2 times Rs1 over Rs1 plus Rs2.

This again right here is multiplied by both of them.

This gives us a circuit that has positive,

both of these are positive,

this value is positive,

this is positive, this is the non-inverting part that we

have no change in the polarity or the positive-negative of our values.

So, we could bring Vs1 and Vs2 into

a circuit where we're going to multiply each of them by a separate value,

a gain term, and then we're going to bring them

together and add them up and that gives us the V out.

This is what a non-inverting summer does.

Remember that as with all of our op-amp circuits,

the value of V out is still limited between

the two power supply voltages Vcc and minus Vcc,

we can't get any bigger or smaller than the

power supplies that we're using, and there's our circuit.