1
00:00:00,080 --> 00:00:04,620
>> In this video, I would like to review what a non-inverting summer does.

2
00:00:04,620 --> 00:00:08,630
We begin by starting with a non-inverting amplifier that you see here,

3
00:00:08,630 --> 00:00:12,335
where you have a single input voltage going to a single output voltage.

4
00:00:12,335 --> 00:00:15,885
Then, we're just going to start adding input voltages to it.

5
00:00:15,885 --> 00:00:21,855
So, we've got this Rs2 with a second voltage Vs2.

6
00:00:21,855 --> 00:00:28,170
What happens over here is that this side acts somewhat like a voltage divider,

7
00:00:28,170 --> 00:00:31,260
and so we're going to have an additional gain term over here which is

8
00:00:31,260 --> 00:00:36,150
Rs2 over Rs2 plus Rs1,

9
00:00:36,150 --> 00:00:45,210
and then we're going to add in our second voltage Vs2 times Rs1 over Rs1 plus Rs2.

10
00:00:45,210 --> 00:00:49,145
This again right here is multiplied by both of them.

11
00:00:49,145 --> 00:00:53,075
This gives us a circuit that has positive,

12
00:00:53,075 --> 00:00:54,649
both of these are positive,

13
00:00:54,649 --> 00:00:56,419
this value is positive,

14
00:00:56,419 --> 00:01:00,320
this is positive, this is the non-inverting part that we

15
00:01:00,320 --> 00:01:04,519
have no change in the polarity or the positive-negative of our values.

16
00:01:04,519 --> 00:01:10,580
So, we could bring Vs1 and Vs2 into

17
00:01:10,580 --> 00:01:16,715
a circuit where we're going to multiply each of them by a separate value,

18
00:01:16,715 --> 00:01:18,920
a gain term, and then we're going to bring them

19
00:01:18,920 --> 00:01:22,900
together and add them up and that gives us the V out.

20
00:01:22,900 --> 00:01:25,055
This is what a non-inverting summer does.

21
00:01:25,055 --> 00:01:29,005
Remember that as with all of our op-amp circuits,

22
00:01:29,005 --> 00:01:32,810
the value of V out is still limited between

23
00:01:32,810 --> 00:01:37,490
the two power supply voltages Vcc and minus Vcc,

24
00:01:37,490 --> 00:01:39,935
we can't get any bigger or smaller than the

25
00:01:39,935 --> 00:01:43,710
power supplies that we're using, and there's our circuit.