Op-Amp: Summing Amplifier (Inverting and Non-Inverting Summing Amplifiers)

In this video, the inverting and the non-inverting summing amplifiers using op-amp has been discussed along with the derivations.
In this video, it has been discussed that how by applying multiple inputs to either inverting or the non-inverting input terminal of the op-amp, it can be used as summing amplifier (as adder circuit)
Inverting Summing Amplifier:
In this configuration, the inputs are applied at the inserting end of the op-amp.
The advantage of this configuration is that each individual inputs are isolated with respect to each other and there is no interference or cross-talk between the different input voltages. (because of virtual ground)
However, the output voltage is inverted with respect to input voltage. And it can be further inverted by using one more inverting op-amp with unity gain at the output of the summing amplifier.
In most of the practical applications, this inverting summing op-amp is used.
Non-Inverting Summing Amplifier:
In this configuration, the inputs are applied at the non-inverting end of the op-amp.
In this configuration, the calculation of the output voltage is getting complicated as the number of inputs increases. Moreover, there is cross-talk between the different inputs. (Inputs are not isolated with each other)
In non-inverting summing amplifier, the output voltage is in phase with the input voltage.
Application of Summing Amplifier:
1) As voltage adder, scaling, averaging circuit
2) To provide the DC offset to the input signal
3) Digital to Analog Converter (DAC)
4) Audio Mixer
The timestamps for the different topics is given below:
0:51 Inverting Summing Amplifier
4:48 Scaling and Addition using Summing Amplifier
5:29 Averaging operation using Summing Amplifier
6:40 Application of summing Amplifier
9:26 Non-Inverting Summing Amplifier (with two inputs)
12:51 Non-Inverting Summing Amplifier (with three inputs)
The link to the related videos on the op-amp:
Introduction to Operational Amplifier:
• Introduction to Operat...
Inverting Op-Amp:
• Operational Amplifier:...
Non-Inverting Op-Amp:
• Operational Amplifier:...
This video will be helpful to all the students of science and engineering in understanding the inverting and non-inverting summing amplifier.
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[@charleselliott4943]

nice, simple, clean explanation. this guy is in a small group of people who know how to make difficult things easy to understand. thank you.

[@NgangAdriel-ju5zs]

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[@poojashah6183]

This op-amp series is incredibly good 👌👌

[@dolonghanty3854]

App feedback or integrater kha se pare ho

[@roxinnjeru5837]

i'm very grateful for your videos about op-amps .i'm using them to revise for my exams coz i do my bachelors in chinese and sometimes i don't understand in class but now i'm understanding everything through this video.

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Man thank you so much for preparing and sharing these videos! I am an undergraduate student as a mechanical engineer and I am studying for my final exam by your videos!

[@mahekvanjani1561]

+1

[@chamed5277]

This illustration of Amplifiers is outstanding. Well done! Thanks you so much!

[@이즈나]

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[@pallavijadhav9231]

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[@bonitalexie3637]

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[@Skystrike70]

Well done, came for quick study help and got what I needed in the first 5 minutes.

[@livelovelife777]

wow..a very nice explanation with so much of clarity...😍👌👏

[@noweare1]

So glad I found your channel. Much better than going to school. I don't even have to raise my hand.

[@balapranav7096]

Thank you so much, sir! You taught in a way no one could, and as the same student who slept when my professor handled this, loved listening to your teaching with great attentiveness... You made this more interesting, while our sir made it look cumbersome

[@poojap9590]

thanks a lot, was slogging the whole semester in this chapter, thank you so much for making it so simple🙏🙏, hope to watch many more topics like these 👍

[@imadyoucef2692]

Your explanation is incredibly perfect Sir, thank u

[@RajasAgarwal]

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[@naturesaver7895]

Sir,thanks for video on electronic,before I had little confusion in learning electronic devices. But now it is clear with ur video ...l will watch all of ur videos sir .

[@poojashah6183]

Amazing, all doubts cleared, thank you so much 🙏🏻

[@RohitSingh-hc8yi]

U bring conceptual clarity to me thanks a lot

[@nayanjadhav2334]

Thank you all about electronic you are favorite teacher . Thank you Thank you so much 😌

[@apostolosmavropoulos177]

TOP CONTENT.. You deserve more subs

[@v.prasath3130]

This opamp series in incredible! Deep and lucid style of explanation makes us to understand concepts in much simpler way! One doubt from above video, sir you have said individual voltages we apply in inverting summer will be separated due to virtual ground and effective input impedance will be the R1. What will happen if all three voltages are given at a time? Pl can u elaborate on how each sources acts separate and input impedance doest not change after adding multiple resistance on input side? Thank you

[@ALLABOUTELECTRONICS]

Actually, all the sources are applied simultaneously. But for the analysis, we are applying the superposition theorem. When you consider one source at a time, then the remaining source will be zero. And if you look the circuit, due to virtual ground both terminals of the resistors will be at ground potential. So, it won't affect the impedance of the circuit. I hope it will clear your doubt.

[@v.prasath3130]

@@ALLABOUTELECTRONICS tq 👍

[@lokendrasinghlodhi718]

Thank You So Much Sir For this effort to help all of us !

[@vinaychourasia652]

Very helpful and zero confusion concept... So very thanks

[@AKASH-sw9bs]

thanks sir . you helped me understand a tough topic and i helped you by disabling adblocker🎃♨️. as usual i use ad blocker but when i watch any educational video i turn it of and reload the site so that the ads can run . though it might seem funny but if everyone would do in such a way that it could result in a beautiful amount 🖤❤️❤️

[@swethachiliveri853]

One doubt: Why did we not consider the concept of virtual ground in case of non-inverting summing amplifier? Thank you for your lectures.

[@ALLABOUTELECTRONICS]

It has been considered. And based on that only, we got Vo = (1 + Rf/ Ra) *V+ . Once, we got V+ using the superposition theorem, then using the concept of virtual ground only, we got Vo = (1 + Rf/ Ra)*V+. In the earlier video of non-inverting op-amp, since I have already covered it, so here I have directly used the expression. For more info, you can check that video. kzbin.info/www/bejne/q6qyl6Kkh8Sle9ksi=ichrOUKxnM8PcJ-y

[@tpsicmin]

Amazing Explantion Thank you Sir

[@akshayasubramanian4311]

Excellent series! Thank you so much!!

[@Samsque90]

I'm wondering which software do you use to make such a wonderful video?

[@dakshitaakarthi2477]

Great video 👌! It would be helpful if u could share the ppts/slides that u had used in the video.

[@reubenwilliammpembe667]

you are the best Sir!!!

[@alishakatyayani7910]

this series is really good

[@abdelrahmanhabib5991]

Hey since you just commented like 5 days ago could you please explain to me why at 6:00 Rf/R=1/n ? I can't seem to be able to understand why

[@abdelrahmanhabib5991]

nvm i realized it was an assumption that he made

[@nekodasaunders9190]

Your videos are really good especially this op amp series..but at times I get trouble understanding what you say..can you add subtitles?

[@nekodasaunders9190]

Oh don't bother.. I opened it on my laptop and there are subtitle..my bad🤦🏾‍♀️

[@apsrv-h2x]

op brooo🔥🔥🔥🔥 it help mee a lott thank u bhayya😍😍😍😍

[@lakshmidaravathu4779]

Thank you so much sir.. Amazing explanation. It's really superb..

[@flobbie87]

Is there anything harder than making sure that two resistors have the same resistance?

[@samrawitlegesse6687]

Thank you sir nice and clear explanation. But my question is When we about the advantage of non inverting in the previous video, infinite input impedance was one advantage right? So why do we put R1,R2 and R3?

[@ALLABOUTELECTRONICS]

Without the resistors R1, R2 and R3, if you directly connect the three voltages at the non-inverting terminal then it will violate the KVL. Basically, you are connecting three different voltages at the same node. But with resistors, because of the drop across it, it won't happen. And you can find the effective voltage at V+ using the superposition theorem. I hope, it will clear your doubt.

[@shreeshkulkarni3657]

You are the GOAT bruh

[@omidabed7764]

Amazing, useful. ... Thank you for sharing

[@sujeetrockson9285]

Good video dear

[@chandsureja6582]

nice content sir keep up the good work sir

[@slheisa8418]

This was very helpfull.Thank you

[@mainakpradhan6175]

And sir also plz upload some videos on working procedure of filter circuits(i mean how the charging discharging of capacitor, inductor helps in smoothing the ripple )....plz sir upload some videos on these, plz sir, please

[@vathsalmehta3488]

My question is why voltage division took place only on the non inverting configuration when we employed superposition theorem what if we employed superposition theorem in the inverting config will voltage division among resistors will take place or not?

[@ALLABOUTELECTRONICS]

In the case of the inverting configuration, if you apply the superposition theorem, then only once source will be active at a time. For example, V1 is active and V2 and V3 is zero. That means one end of the resistor R2 and R3 will be at ground potential. Also, due to the virtual ground, other terminals will be grounded. That means both terminals of R2 and R3 will be at ground potential. And they will act it as if they are not the part of the circuit. So, there is no point of applying the voltage divider rule. I hope it will clear your doubt.

[@vathsalmehta3488]

@@ALLABOUTELECTRONICS Thank you this was helpful

[@arijeetroy8747]

@@ALLABOUTELECTRONICS sir in non inverting we can also do the same thing , active only one source and rest of two source will be grounded then how we can apply superposition theorem , and in the non inverting summing amplifier you are also doing the same thing, grounding V2 , calculating V1 . please clear my doubt ?

[@bhageshmaheshwari2807]

Nice video again. Can you please elaborate why there would be cross talk between inputs in non-inverting config but not in inverting one ? Thanks.

[@ALLABOUTELECTRONICS]

In case of the inverting configuration, due to virtual ground, one end of the resistors is connected to the ground. When we consider one source at a time and consider all other sources as zero, (to find the output), then both ends of resistors (For those input signals which are considered as zero) will be at the ground. So, effectively there is no impact of those voltage sources on the output. But that is not the case in the non-inverting configuration as I mentioned at 16:22. I hope it will clear your doubt. If you still have any doubt then let me know here.

[@rhp1234]

Sir, keep it up👆👍👍

[@praveenm5278]

Your answer is right but we can't apply superposition theorem for bilateral circuits as we know all semiconductor devices are bilateral or non linear so prove that

[@ALLABOUTELECTRONICS]

The op-amp is used in the linear region, so superposition theorem can be applied.

[@praveenm5278]

I think we can't apply our sir told us proof tell me proof

[@VijendraSingh-bp3sf]

Superb explained 🏆🏆

[@younis-jw8sw]

The 741 ic connected as a non inverting amplifier for a gain of 100. Determine the stability of the amplifier at this gain

[@ALLABOUTELECTRONICS]

well, actually it depends, what is the input signal frequency, and what is the input voltage. Because when op-amp is used with negative feedback, then stability is a function of frequency. For, small DC voltage (in mV), the output will be stable. With the gain of 100, it will be in Volts. But let's say, if you apply an input voltage of 10V, in that case, you won't get 1000V at the output. Rather output gets saturated at the Vsat voltage. For +15V supply, possibly you would get around 12-13V at the output.

[@ramilawijesuriya7259]

Excellent video ! Thanks

[@mayurshah9131]

Really very informative

[@-MDRaselMia]

In case of I(f) current direction will opposite as current flow higher potential to lower potential... V(out)>node potential 0

[@adhithyan9444]

you are really great.

[@ElectricalEngineeringApp]

very good video sir thanks

[@RohitRai-vz2vn]

U are legend what a content

[@anya7094]

Can anyone please tell me what is meant by providing dc offset to the input signal?

[@LI-hz2me]

sososo helpful! thank you so much!

[@happylifehappywork7543]

different input voltage with different resistors value. which formula we will use?

[@deepakdaswani7929]

Sir can we Rf equals to 0 in non inverting summing amplifier so it can act as average amlifier ?

[@YogendraKumaree24m566]

If one more resistor R4 is added but without any voltage source, will R4 will affect the calculation of v1+.

[@ALLABOUTELECTRONICS]

In case of non-inverting summing amplifier, the additional resistor will make a difference in the calculation in V1+. Because, while applying superposition theorem, along with R2 and R3, the R4 (additional resistor) will also come in parallel. So, now the calculation will change.

[@rk5759]

For God's sake change the intro music else you are doing a good job

[@Karan_Adhikari]

Sir what is the maximum output voltage produced by a summing amplifier?

[@ALLABOUTELECTRONICS]

Depends on the biasing voltage of the op-amp. The biasing voltage decides the positive and the negative saturation voltage of the op-amp.

[@swapnilbhoite902]

Good work!!!

[@MrXinchuan]

Can you explain in the superposition theorem, why v1+ =(R2*V1) / (R1+R2), but not v1+ =(R1*V1) / (R1+R2). I can't find any explanation about this voltage division rule.

[@ALLABOUTELECTRONICS]

First, let's assume that when V1 is acting alone, then the total current in the loop is I. So, I = V1 / (R1 + R2). Now, the voltage V+ is actually a voltage drop across R2 right !! And using ohms law, we can say that, V+ = I1*R2. Now, putting the value of I, further, it can be written as V1*R2 / (R1 + R2). So, that is a voltage divider rule. In that equation, V1/ (R1 + R2) is the total current in that loop. I hope, it will clear your doubt.

[@mdshadab9170]

sir,how did you put superposition throrem while discussing about non inverting op amp. I am finding difficulty understanding it, plz help.

[@debaprasadadash4824]

Actually it is easy to understood a student.

[@aryantewari]

thank u sir

[@Shen-w9q]

Thank you very much for sharing this video. I have a question: how to do input bias current compensation then in the summing circuits?

[@bluecrystal5636]

How can we get v0 in inverting summing amplifier with superposition theorem

[@aasheervadsharma1016]

Thanks for the videos really it was nice Sir plz tell what if we apply different signals at both the terminals of a summing Op-amp

[@ALLABOUTELECTRONICS]

Hi, you mean to say, if Vin1 and Vin 2 are different then what would be the output?

[@aasheervadsharma1016]

Hello My question is that in a single opamp if we apply some signals( like V1a, v2a, v3a etc.) on positive terminal and some signals (like v1b, v2b, v3b etc. ) on the negative terminal in that case what will be the formula for output??

[@ALLABOUTELECTRONICS]

I have discussed that in the separate video. Please watch the video on the differential amplifier. You will get the answer. And after that still, if you have any question then do let me know here.

[@justchill4873]

Can u put videos about regulated power supply sir..plzzzz

[@ALLABOUTELECTRONICS]

I have already made a video on it. Please go through op-amp as voltage regulator video.

[@justchill4873]

@@ALLABOUTELECTRONICS thank u sir

[@Aditya-kumar-129]

I think u haven't made video on this topic "Op-amp as subtractor" Please see to it

[@ALLABOUTELECTRONICS]

Please check the video on op-amp as a differential amplifier. Here is the link : kzbin.info/www/bejne/oqW5pKOLqcqoq6s

[@technovisionpk6974]

where and why we use summing inverting/non inverting amplifier

[@md.hafizsikder4152]

It is frequently called a signal mixer as it is used to combine audio signal from several microphones, guitars, tape recorders, etc., to provide a single output. Hope that helps. Happy Learning.....

[@akshithapandya1918]

Amazing, good explanation 😊 Tq for helping in this 😀

[@surendrakverma555]

Good 👍

[@shiblnasser7151]

U r awzm great explanation

[@thusharanup4906]

what if there is a voltage source on the other terminal? e.g non inverting amplifier has a voltage source in the inverting terminal or vice cersa?

[@ALLABOUTELECTRONICS]

I think you are talking about the difference amplifier where there is a voltage source on both positive and negative terminals, isn't it? There is a separate video for that. Please check it.

[@rakeshgehlot9590]

Wonderful guru ji

[@vinaykumarkv5830]

Very goodexplaination

[@sateeshkumar8106]

Which one is best inverting or non inverting amplifier?

[@Shanaya-2002]

Did you get the answer? Which one is better?

[@zenvir1680]

At 10:40 the resistance of the OP-Amp is infinite, shouldn't all the voltage V2 drop across the Op Amp itself and thus making V2+=0 ? I am confused at that exclusion of OP-amp's infinite resistance from the circuit

[@zenvir1680]

Oh!! I solved by individual currents and added them, got the same value for V2. But when we take currents in consideration we can say current will not enter Op-amp due to infinite resistance, but how do we explain the same with voltage?

[@ALLABOUTELECTRONICS]

@@zenvir1680 If there is a current flowing through any resistor, then there will be a voltage drop across that resistor. It is independent of the resistance of the op-amp. At the non-inverting terminal, the current is flowing through R1 and R2. And the voltage drop across the R1 is V2+.

[@zenvir1680]

@@ALLABOUTELECTRONICS I got that. Thank you so much.

[@tamannasharma1568]

sir if the input impedance of an opamp is very high then there will be no flow of current so, whether the opamp circuit in off state OR NOT?

[@ALLABOUTELECTRONICS]

Actually there is a flow of little current ( in uA). But for ideal opamp it is zero. More over, through bias voltages, opamp also draws the required current for the operation. I hope it will clear your doubt.

[@basilbenedictvictor2053]

Does this also follow the same concept of biasing voltage as shown in the differential amplifier

[@ALLABOUTELECTRONICS]

Yes, it does.

[@mahimatolani2447]

Why didn't we apply concept of virtual ground in non inverting summing amplifier..it also uses negative feedback??

[@ALLABOUTELECTRONICS]

In case of the non-inverting summing amplifier, V+ terminal is not at ground potential and same is true with inverting terminal. But because of negative feedback, there will be virtual short between inverting and non-inverting terminal (V- = V+)

[@abhisheksingh-pv3gm]

Sir Which software u r using for making videos.

[@waelsadek81]

Very good videos 👌

[@rohitgarg1814]

Ans is 4V......if wrong then plzzz tell write ans...

[@tamannasharma1568]

Sir, how the bias voltage is placed in the circuit ? And sir ,which book should i prefer to study the opamp?

[@rectifiedrandomness]

Op Amps and linear integrated circuits .- Ramakant A Gayakwad.

[@s.jayanthKumar-w3q]

i have a doubt....that is u have applied superposition theorem for v1 then u have to take series resistance but u taken parallel resistance that is for v1 u have to take r1/r1+r2 but u taken r2/r1+r2.

[@ALLABOUTELECTRONICS]

Would you please mention the timestamp where you are referring to in the video ?

[@ALLABOUTELECTRONICS]

Ok, I got it where you are referring to. See, here we are applying the voltage divider rule. While applying superposition theorem, If you just consider V1 voltage source alone( and V2 as 0V), then voltage at the non- inverting terminal is V1* R2 / ( R1+R2). Please check the voltage divider rule for resistor once again, you will get it. And if you still have any doubt then let me know here.

[@sayandey7956]

Please send some important question from this op amp

[@ALLABOUTELECTRONICS]

Please check the community tab section of the channel. You will find many questions related to the op-amp. Also, I have made two dedicated videos in the questions based on the op-amp. Here is the link: kzbin.info/www/bejne/jJWzZKeKmMaNf8U

[@prashantgourav1485]

Bro pls consider making videos in HINDI in an alternative channel please. It would be really helpful in understanding the concepts.

[@divyangthakkar1074]

What happens when multiple inputs are applied to the inverting and non-inverting sides together?

[@ALLABOUTELECTRONICS]

In that case, op-amp can be used as differential amplifier/difference amplifier. It is also known as the subtractor circuit.

[@ajaysauravminhas1191]

Please anyone tell me that how these voltages got calculated with resistance ....and which formula used here .

[@samvolcom1]

At 12:20 when you say R1=R2=R , what's R in this equation because it is not on the drawing ? Thank you!

[@ALLABOUTELECTRONICS]

What I mean to say is, if both resistors are equal then in that case, you will get (1 + Rf/ Ra) (V1 + V2)/2 R is just for representation to indicate that, the value of two resistors are equal. I hope it will clear your doubt.

[@samvolcom1]

@@ALLABOUTELECTRONICS yes thank you!

[@subhrajitghosh7017]

But sir if we apply voltage divider rule for non inverting terminal....the voltage at that point does not become equal to that in the inverting terminal .........I am talking about the case of inverting summing amplifier......sir please explain

[@ALLABOUTELECTRONICS]

Hi, I didn't get your question. For the inverting summing amplifier, the non-inverting terminal is grounded.

[@subhrajitghosh7017]

Sorry sorry I mean to say what if I apply voltage divider rule in the inverting terminal of the inverting summing amplifier.....

[@bijum2086]

really helped me

[@younis-jw8sw]

Please give solution 741 if connected to non inverting amplifier for a gain 100. Determine stability of this amplifier

[@ALLABOUTELECTRONICS]

Would you please provide the exact question so that I can help you.

[@harun-or-rashid8714]

Sir, Please make a video on linear digital IC.

[@ALLABOUTELECTRONICS]

Soon I will make it.

[@azamali3237]

Sir one non inverting op amp can performs the sum on the other hand we use two op amps Isn't disadvantage ?? And other questions Is that sir if we apply the node analysis it's complicity will reduce ... So why we don't use this non inverting in a practical life sir??

[@azamali3237]

Non inverting summing op amp

[@ALLABOUTELECTRONICS]

In non-inverting summing amplifier, as the number of input increases, the complexity in the calculation will also increase. Moreover that, the individual input that appears at the noninverting terminal also depends upon the series resistors of the other inputs. In case of inverting op-amp, individual inputs are isolated to each other because of virtual ground. And it is a big advantage. That's why practical circuits like DAC are implemented using inverting summing amplifier. I hope it will clear your doubt.

[@azamali3237]

Sir What about overall efficiency ? How much these resistor effects on the efficiency ?? What are the practical losses !? In non inverting summing op amp

[@azamali3237]

Sir I have also a question regarding non inverting buffer op amp .... Sir if we apply 5 volt on the non inverting terminal and short the inverting terminal with feedback... After first step the out put of 5 volt will appears at out put side of the buffer and that out same is feedback to the inverting terminal so now the difference between in put is zero and this time out put should be zero so it means the gain is not 1?? Plz sir guide me ...

[@ALLABOUTELECTRONICS]

For all the derivation of inverting and non-inverting op-amp, we have assumed that the op-amp is ideal op-amp. And it has a very high gain. Providing the negative feedback we are restricting the output voltage. So, for that output voltage and considering very high gain of the op-amp, input should be very low. (difference between two input terminals). Typically in microvolts for very high gain. So, we can assume that both input terminals are at the same potential, which is the concept of virtual short. So, we are assuming that the difference is zero between the two inputs, but actually, there will be some difference of microvolts between the two inputs. So, actually, your output is the input voltage (the difference between the two terminals) multiplied by the gain of the op-amp. I hope it will clear your doubt.

[@VijendraSingh-bp3sf]

Keep going 🏆🏆🏆🎖️

[@muzammilrizvi6424]

Amazing 😍