Schmitt Trigger Explained (Design of Inverting and Non-inverting Schmitt Trigger using Op-Amp)

[@ALLABOUTELECTRONICS]

The timestamps for the different topics covered in the video is given below: 0:28 Limitation of the comparator circuit 2:00 What is Schmitt Trigger and how it works? 4:15 Hysteresis Curve of Inverting and Non-Inverting Schmitt Trigger 8:00 Design of Inverting Schmitt Trigger (with Derivation) 12:50 Design of Non-Inverting Schmitt Trigger (with Derivation) 18:30 Application of Schmitt Trigger

[@sharonyabanerjee2867]

Please tell

[@abaundwal]

Hi. I have a doubt. What determines V (high) and V (low)? Are they equal to +Vcc and -Vcc respectively?

[@Asitiaf]

@@abaundwal V(high) can be sometimes equal to Vcc. To be more specific, V(high) is the Saturation voltage when a positive input (V+ - V-) is given to op-amp. However, many a time, Saturation voltage may be equal to Vcc or slightly less than it.

[@noweare1]

Don't watch this video if your tired. I had to go through it three times especially for the non-inverting Schmitt Trigger. Has a lot of math associated with it for such a simple device. Great video, I feel I understand it much better and now can design with it.

[@xRevollt]

bro it's trivial en tabarnak juste un diviseur de potentiel pis that's it

[@charankumar5067]

Yeah me too had a tough time understanding it😅

[@vaishrox66]

You underestimate my power to study at the last minute at 4 am in the morning. I'm very tired...

[@ak689]

@@vaishrox66 you're extrovert and lonely, how?

[@anjalipravallika9999]

Same u know, I don't get it, 5 times yesterday night, just 10min today morning, I understood very clearly🥹

[@aniksingharoy59]

I wonder why this channel has 237k subscribers only!!! He deserves much more Love your explanation Sir❣❣❣

[@circuitsanalytica4348]

Yes Anik, he deserves more subscribers....

[@amitrajput6904]

Only 1 percent engineering student watch this channel .

[@klaus2t703]

As a professional electronics designer with decades of deep experience.... In my eyes the video misses to explain expectable problems. For example I woder why they use an OPAMP because not every OPAMP can do this. Some OPAMPs my burn (violating diff_V_IN), some OPAMPS may create crazy output (phase reversal). If you want saturated output it´s always the safe way to use a comparator (instead of OPAMP). There is a good reason why there are OPAMPS and COMPARATORS, they are not the same thing.

[@anonymous9217w2]

@@klaus2t703 chup hai hume samaj mai aa rha ha dimag mt laga

[@starlordhero1607]

@@klaus2t703 Bro, I want to have knowledge like you. Do you have any suggestions on what to do? Or any YT channel that tells stuff like this?

[@akloveforphysics]

This Man..... Is Genious !!! Thank you sir poora youtube dekha, aapke itna best kisine nahi samjhaya... watching it 2 days before exam...

[@styrishrodrigues]

He has 6Lakhs subs now

[@radhakrishnanrayaprolu]

All praises to you Sir! you saved me for my Semester

[@ahmadal-tarabeen9253]

You make me understand something that my proff can't explain it for me,

[@saikarun5834]

Yes bro! Better electrical engineers are made from KZbin rather than universities! 😬

[@maxfrancky7615]

Thank you for your very clear explanation sir. Watching from Madagascar

[@vishvakapadiya3051]

I come back here whenever I find trouble in transfer curve. All of my doubts gets solved. Thank you ❤️

[@HUALEX1988]

great content! It really helps me a lot when I am learning this stuff all by myself.

[@nthumara6288]

me too.this is really helpfull for self study students

[@solapowsj25]

Good method and teaching. I wish you success as lecturer and best of luck in your profession.

[@stanfordkoga-zs9nh]

You are a good Amplifier when it comes to simplifying

[@vedantagrawal1572]

Thank You Sir for providing such a great content, we have our exams next week and your videos lectures really helped me in clearing all of my doubts for the subject, once again thanks a lot for posting such informative content

[@ogbuddha7835]

10:21 : you said Vin > V1 then output will be Vut _Doubt_ : What when Vin < V1 ? How will be the output?

[@anonymous-qn6sv]

00:12 Schmitt Trigger is a comparator with hysteresis 02:32 Schmitt Trigger provides noise immunity over a band 04:57 Schmitt Trigger has a transfer characteristic curve known as the hysteresis curve. 07:32 Learn how to design inverting and non-inverting Schmitt Triggers using op-amp. 09:56 Inverting Schmitt Trigger has upper and lower threshold voltages 12:32 Designing Schmitt Triggers using Op-Amp 15:12 The upper and lower threshold voltages for a non-inverting Schmitt Trigger 18:01 Schmitt Trigger can be used as a level comparator, wave shaping circuit, and oscillator. Crafted by Merlin AI.

[@shaillybhai007]

Thanks for the video. I have one doubt. Will the concept of virtual ground not applicable in Schmitt trigger? Kindly reply.

[@ALLABOUTELECTRONICS]

No, because it's applicable only when the opamp is used with negative feedback. In Schmitt trigger it is used in positive feedback configuration. So opamp is operating in the saturation. That's why it's not applicable.

[@shaillybhai007]

@@ALLABOUTELECTRONICS thanks for your prompt reply. Sir, what is the reason that virtual ground is only applicable in negative feedback?

[@bhandai]

Too good expained.. Thank you.. 🎉🎉🎉

[@wojciechg9498]

You should get a noble prize in teaching. thanks

[@circuitsanalytica4348]

Exactly....

[@MUTHU_KRISHNAN_K]

Sir I have some doubts Why we use positive feedback? Does virtual ground concept act here too? How can we fix a specific voltage as UTV and LTV?

[@ALLABOUTELECTRONICS]

Here we are using positive feedback, because we want the opamp in the saturation. That means it has only two output states. + Vsat and - Vsat. And the virtual ground concept is not valid the the positive feedback. It is only valid with the negative feedback, when the opamp is operating in the linear region.

[@MUTHU_KRISHNAN_K]

@@ALLABOUTELECTRONICS thank you very much for your valuable reply sir 🙏

[@Subharambh5420]

It's an amazing lecture. It clears all my doubts . But I have request for you can you provide written notes on opamp

[@crystalclear8395]

bsdk sab yehi kar de tu khali laar chaat

[@embeddedvisions3508]

Is it possible to detect Reverse and Forward flow of IR using this schmitt trigger ?

[@koralina33]

Hello, Would You explain to me, how did I get shift of transfer characteristics, for example: VH=2V, VL=-3V (not -2,5 and 2,5 as usual)? How is this possible? I've been using Hall sensor with Schmitt trigger for multipole magnetic encoder and on the output I got signal with 1/3 duty cycle, instead of 1/2 duty cycle (poles are equal, but reverse in sign). Does transfer characteristics shift depend on Vref? How did we get Vref - I mean once per measurement (on the every begining of each multipole encoder measurement it takes valuse dependent on first pole it measured and it is constant through whole measurement) or every time we cross VL or VH threshold? Does characteristics shift constant through whole measurement (if it is) or does it change every time we cross VL or Vh threshold? I would be very greatful for Your response!

[@VijayKumar-qg5zb]

Extremely....... Clear explanation sir......

[@royalenfieldmeteorrider7873]

Vut=Vref+(Vref-Vlow)*R1/R2 Vlt=Vref+(Vref-Vhigh)*R1/R2 Is the formula of upper and lower threshold voltage correct for Non-inverting scimitt trigger with reference voltage?

[@aksharasajeev9746]

thank you sir for giving such a clear explanation you are superb

[@ashishrajput4646]

Sir in non inverting st you say ki v1>0 then output is high similarly when v2

[@circuitsanalytica4348]

Dear Ashish, something is missing ....

[@siddhisahu7220]

Schmitt trigger is a ___ voltage comparator.(+ve,-ve,both,none) sir what is the answer of this

[@punyavathijanni2771]

Which software is used to make circuit diagram and graphs 📊

[@zZerozZz]

Very helpful video, this helped me get through my finals, thanks a lot!

[@girishmahajan4130]

Excellenttttttttt........Explanationnnnnnnnnn..

[@shubhabratadutta9790]

We want more topics sir.You starts from the basic..

[@vinuramendis2273]

you are the best

[@srinjoyghosh3089]

Extremely clear explanation. Love it.

[@agstechnicalsupport]

Schmitt Trigger using Op-Amp well explained !

[@parththosar1097]

in the beginning when the input crosses lower threshold voltage, why does the output not change accordingly?...just in the beginning?

[@abdelazeemhassan3701]

Amazing as usual

[@VAISHNADEVIGECEUG-]

THANKS FOR YOUR EFFORT SIR

[@ogbuddha7835]

At 10:07 you said to take Vout = Vh (Vh is high output when V+ >Vin)... On the next equation you asked so consider Vin > V1. TO get VLow _Doubt_ : _We have already considerd V+>Vin to obtain Vout=Vh and named it as V1 now how can you again compare Vin and V1 to get VL. And how is Vlow consider as Vut? Please sir I'm stuck badly in this confusion_

[@lolvivo8783]

Did u get the answer?

[@Mrlonelyuploader]

For understanding it Initial Assumption was made :- Vin < V + , then Vout = VH Now, the output will remain VH till Vin < V . This is considered as V1. Comment :- "On the next equation you asked so consider Vin > V1. To get VLow" . Yes because unless the Vin doesn't goes less than V1, the output will remain LOW only. We need to get the VH as output as well. Now when Vin > V1 , then the output becomes VL ( Low). Case 1 :- Voltage is set at VH > Vin . The output is low. (V1) When Vin < VH the Vout is becoming HIGH.

[@1simc1]

thaaaaank you, better than my uni teacher

[@joshfoulkes5327]

For the inverting Schmitt trigger is VL and VH the voltage supplied the op-amp as in VCC

[@lorenzobongiovanni6398]

yes, both for inverting and non inverting

[@sp3associate]

Sir can u pls make a dedicated video on hysterisis ?

[@pronounceword]

Hi.I like your video very much. It's really great. I'll keep an eye on your channel. I am your fan and I will support you.

[@circuitsanalytica4348]

Yes, friend you said it right....

[@SureshSuresh-xs8bj]

Sir may you please explain what is noise immunity here

[@rizwanriaz7595]

excellent appriciated,wellexplained.liked vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv much

[@GauravKumar-oy3rj]

In non inverting case if Vout is low then V^+ is less than 0 ie V^+=r2/(r1+r2) + r1/(r1+r2)*Vl not Vh.........can u explain why u wrote Vh instead of Vl

[@sharonyabanerjee2867]

Why you don't use inverting sc hmit trigger circuit? Is it not happen with referrence voltage

[@rachanapurohith]

Your explanation was awesome 🤗. Thank you

[@devensingforpeace6204]

Explanation is very nice..thanq sir But the voicenotes are disturbing the video during explaination 😊

[@emreipek4485]

Many thanks for the video :)

[@grjesus9979]

if it is positive feedback how the output doesnt get infinite with time?

[@ALLABOUTELECTRONICS]

Even with the positive feedback the output can't go beyond the supply voltage isn't it ?? And that's why the output gets saturated at the supply voltage or the Vsat of that op-amp. I hope, it will clear your doubt.

[@Siamg-b4b]

@@ALLABOUTELECTRONICS yeah but the question is that why do we see saturation voltage at the ooutput? why dont we see less output voltages? using negative feedback or positive feedback whatever using closed loops we can set gain. so what if the gain is less?

[@ALLABOUTELECTRONICS]

@@Siamg-b4b when the positive feedback is more than negative feedback then eventually, the output will get saturated.

[@Siamg-b4b]

@@ALLABOUTELECTRONICS got it. thanks

[@sharonyabanerjee2867]

@all about electronics schmit trigger is a circuit positive feedback applied to the comparator.is it right?

[@circuitsanalytica4348]

Hello, Schmitt Trigger is basically a comparator, with positive feedback...

[@faneeshbansal]

Sir why we have only taken positive feedback i.e non inverting feedback in Schmitt trigger?

[@ALLABOUTELECTRONICS]

When the op-amp is used as a Schmitt trigger then it is used in the saturation region of operation. Meaning that, the output of the op-amp is either + Vsat and +Vsat. (Vsat is typically little less than biasing voltages of the op-amp). When the op-amp is used with the negative feedback, then it operates in the linear region, meaning that the output is linear function of input. (e.g V0 = AcL x Vin). But with the positive feedback, when we are using the op-amp in the saturation region, then irrespective of the value of the input signal, the output of the op-amp gets saturated. (either to + Vsat or -Vsat). The Schmitt trigger is intended to work like that, like a comparator but with some hysteresis. I hope, it will clear your doubt.

[@faneeshbansal]

@@ALLABOUTELECTRONICS means when we use negative feedback , then our vout will be lower than the vin, and we don't want that, we want our output to be greater than vin so that it will saturates, right?

[@pradeeppeter5068]

Very good presentation. Thankyou very much!

[@aman_]

You are great. Clear explanation.

[@engrhanan1389]

In case of non inver schmit trgr why we can not put vin at + and feed back resistor on - with ground?

[@ALLABOUTELECTRONICS]

You mean to say like inverting configuration ?? The thing is Schmitt trigger is operated with positive feedback. That means based on input, the output is either + Vsat or - Vsat.

[@ALLABOUTELECTRONICS]

If there is negative feedback, then it's not a Schmitt trigger circuit. I hope it will clear your doubt.

[@tawananyashazhakata8843]

Thanks its so clear

[@1simc1]

and watch out when applying reference voltage because it also has a factor attached to it thanx again

[@HARIkRISHNA-wj6sh]

Bro, before and after, using schmit trigger waveforms I didn't find any difference ,can someone please explain me

[@circuitsanalytica4348]

Hello Hari, with schmitt trigger, the output if opamp is locked for certain range of input signal....

[@HARIkRISHNA-wj6sh]

@@circuitsanalytica4348 ok thank you

[@deepthysivan9020]

Very good video

[@circuitsanalytica4348]

Yes Deepty, really good video....

[@iyyamperumal185]

Super video Very useful Can you upload "555 timer as Schmitt trigger" topic please? Awaiting

[@circuitsanalytica4348]

Hello friend, in my channel, these videos are available...

[@nikshepbangera5416]

why is V+ assumed to be greater than Vout???

[@jeetshah6088]

Great video! , Can you also make a video of Schmitt trigger with BJTs or MOSFETs?

[@daraniweerakkody9079]

great video bro

[@yeshwanthsaikothamasu2133]

How in hysteresis curve,if Vh and Vl equal and opposite in polarity makes hysteresis curve symmetric to y-axis.

[@ALLABOUTELECTRONICS]

It has been assumed that the positive and the negative supplies of the op-amp are equal and opposite in polarity. And usually, it used to be the case for the op-amp. that's why it is symmetric about the y-axis. I hope it will clear your doubt.

[@hammadhassan9409]

how window comparator will operate when VH=VL .Actually i was given a task to design comparator when two voltages are unequal. Need help .

[@ALLABOUTELECTRONICS]

I have made a video on the comparator, where I have explained window comparator. Please check it. Here is the link: kzbin.info/www/bejne/oWrdgp17lrCnnM0 If you still have any question after watching it then do let me know here.

[@arokiachristhuraja7104]

really very good and simple explanation

[@gorakshsingh761]

Easy to learn 👍 Thanks a lot

[@vysakhku102]

Sir why doesn't we consider the virtual ground thing in the case of non inverting Schmitt trigger

[@ALLABOUTELECTRONICS]

Because the concept of virtual ground is applicable only when the op-amp is operated in the linear region. ( During the negative feedback). In Schmitt Trigger, there is a positive feedback. Means op-amp is operating in the saturation region. So, we can't apply the concept of virtual ground. I hope it will clear your doubt.

[@vysakhku102]

ALL ABOUT ELECTRONICS thankyou sir ❤️

[@ayush.tiwarios2105]

00:15 Schmitt Trigger is a comparator with hysteresis. 02:38 Schmitt Trigger determines output based on input threshold voltage 05:01 Schmitt Trigger behavior explained 07:27 Inverting Schmitt Trigger's transfer characteristic curve can be shifted by providing external reference voltage. 09:56 Schmitt Trigger sets threshold voltages for input signals 12:34 Designing inverting and non-inverting Schmitt Triggers using Op-Amp 15:13 Schmitt Trigger has upper and lower threshold voltages. 18:02 Schmitt Trigger has applications in level comparison, analog to digital conversion, wave shaping, and multivibrator and oscillator design.

[@lorenzobongiovanni6398]

I've not understood why (physical why), the behavior of the positive feedback is so different from the negative one, looking at the negative one it is easy to see that V- follows the V+ and doing the KVL across the inverting branch and negative feedback the result will be Vout negative if Vin positive and the opposite if Vin is negative... obviously i cannot do the same with the positive feedback but i don't understand why

[@mdrabbulhassan3059]

why i take Vo= Vth why we dont assuming Vo =0v

[@circuitsanalytica4348]

Bro, Vo cannot be zero as the output of Schmitt trigger will be either at +Vsat or at -Vsat.....

[@gnkumar5951]

thanks and keep up the good work. waiting for lectures on transistor models amplifiers and oscillator

[@ramanapolireddy5040]

For example my +vsat =10 volts if R1=R2 then upper thershold voltage is 5 volts when voltage at inverting terminal is more than upper thershold voltage we will get -vsat then voltage at non inverting terminal is -5 then voltage at inverting terminal should be less than lower thershold voltage right if we calculate this with gain=100 then vout =A(v^+ - v^-)

[@ramanjaneyulujagannadh2668]

Sir ,why does not applicable for virtual ground concept in Schmitt trigger?

[@ALLABOUTELECTRONICS]

The concept of virtual ground is applicable only when the op-amp is operated in the linear region (with negative feedback). Here, in case of Schmitt Trigger, the positive feedback has been applied to the op-amp, so it is operating in the saturation region. I hope it will clear your doubt.

[@ogbuddha7835]

@@ALLABOUTELECTRONICS tysm sir

[@Jnglfvr]

AT 2:13 you have the upper thresh hold voltage sending output from low to high but that is only true for the non-inverting ST. For the inverting ST the upper thresh hold voltage signals the point where the output goes from high to low.

[@andreas_siokos]

indeed !

[@azamali3237]

Thank you so much sir got it please make vedio on examples numaricals of s.trigger

[@ALLABOUTELECTRONICS]

Yes, very soon I will make it.

[@vinlyrix2274]

At 1.32 in the video it's shown that the output voltage becomes zero if the inverting voltage is higer than non-inverting voltage...but you are giving -Vs supply...so the output should be a negatve value(probably -Vs) at the moment...

[@noweare1]

He doesn't say it becomes Zero, he says it becomes low voltage, (what ever the negative supply is)

[@GaganKumar-zk1zu]

Plz send the note in pdf or give the link for notes in description

[@rhp1234]

Pls upload videos on Communication systems

[@ALLABOUTELECTRONICS]

I have already started the series on it. Please check the latest videos. Or you can check this playlist. More will be uploaded in coming weeks. kzbin.info/aero/PLwjK_iyK4LLArUHRm3SvPLT0XWlVhpl4h

[@thejaskingofmagic]

one word...UYIR

[@UECAshutoshKumar]

Thank you sir

[@sharonrhodaelluri6225]

Make an video for schmitt trigger using IC555

[@gauravjalankar1015]

Thanku so much 4 ur guidance

[@dalenassar9152]

Can you make a comparator with Vh and Vl are NOT equal?? Perhaps a diode in series with a resistor? THANKS FOR ALL OF THE GREAT VIDEOS!!!

[@ALLABOUTELECTRONICS]

Yes, definitely. I think I have already covered such example. Please check, opamp solved examples playlist. You will get it.

[@minawetalks]

Thank you sir, great video

[@puspendurana7501]

Can you write your lecture in a blog so that we can collect it as a note .

[@ALLABOUTELECTRONICS]

Yes, you will find some of the notes on allaboutelectronics.org

[@ronakagarwal6781]

I saw this video 2 times but still i am not getting the answer of the Q is how schmitt trigger provides immunity to the noise??? Can u please elaborate more !!!

[@ALLABOUTELECTRONICS]

In case of Schmitt Trigger, whenever input signal goes above the upper threshold voltage then there is a change in the output (Depending on whether the Schmitt Trigger is inverting or non-inverting). Now, even if input just crosses this upper threshold voltage (it goes below the upper threshold voltage), then also output will remain the same. Unless input goes below the lower threshold, the output will remain the same. So, the circuit provides the noise immunity for the change in signal between upper and lower threshold voltages. And that is not the case with comparator. In case of comparator even if input goes just above and below the one threshold voltage, then output will change suddenly. I hope now it will clear your doubt. And still if you have any doubt then do let me know here.

[@ronakagarwal6781]

Thanks a lot!!!

[@jatinsaini4787]

Please make yourself extra clear in deriving the expressions for the lower and upper threshold voltages for the two Schmitt trigger configurations, you assumed some values for V_out in the analysis and that point onwards the further analysis (in both the configurations) gets really mushy.Please redo that part.

[@aadeshaadi1121]

Thanks a lot ☺️

[@jayakumar6780]

Cab any one explain how he compared.. V1>0 with (R2/R1+R2) vin > -Vl(R1/R1+R2)

[@aashishshukla5172]

How can we justify that by connecting non inverting terminal to output will cause +fb & with this, concept of virtual ground becomes invalid at this situation. Please justify or cover in some video lecture. Thanks 😊

[@clashbegins2063]

because of positive feedback

[@sammetakarthik1476]

the video was great and intresting

[@saniyakhatri2660]

Why upper threshold occurs when vin is less than v1 and vice versa?

[@ALLABOUTELECTRONICS]

Would you please provide the timestamp where you are referring to ?

[@saniyakhatri2660]

Vin less than v+ ,9:01

[@HenriqueOliveira-tx7ur]

thank you very much

[@kanjidama2902]

How did u decide current direction?

[@circuitsanalytica4348]

Direction of current depends on polarity of output....

[@the_alokpratapsingh]

Nice

[@jasreenkaur7347]

But you dont provide notes when you explain this, due to which making notes alongside becomes really hectic n difficult task

[@abhisekrout976]

How to solve Qs involving both positive and negative feedback??

[@circuitsanalytica4348]

If there is only negative feedback, then basically that is an amplifier. Wherever there is a positive feedback, then the circuit is an oscillator or its derivative like a Schmitt trigger...

[@LI3AXE]

17:20 Why negative vh?

[@shreyatiwari5934]

Thank you sir, But can you provide us with notes

[@yashwantkumar1951]

very helpful videos sir...