{229} Adjustable Zener Reference TL431 / How To Calculate Programming Resistor To Adjust Feedback

[@paulanderson1687]

Thank you so much for this. I have spent countless hours searching the internet for information as to why I cannot get my TL431 to work. You are the only one who clearly explains the importance of maintaining 2.5V on VRef when using with voltage divider. A very important point to know that everyone else seems to miss. You have helped me immensely with my troubleshooting.

[@HaseebElectronics]

You are welcome! it is my pleasure that my efforts are helpful. please accept my best regards

[@veeem3964]

Very clear explanation thanks for your time & effort

[@ministeriomundialliberando8403]

It's been the same with me: huge hours amount trying to understand the Tl431. This video explain this very clearly. Thanks a lot.

[@olivierj.2435]

Same here, thank you Sir

[@Rodderick45]

Hello once again my friend Haseeb! Another Excellent video on the TL431 regulator and I could not continue on to another one of your Excellent videos without showing my sincere appreciation for such a detailed comprehensive understanding. Your illustration through the use of actual parts and their connections in an actual circuit is invaluable. Words cannot express enough the knowledge you have unselfishly provided to me as I actually had to replace a TL431 and it’s optical coupler repairing the power supply back in 2009 in the repair of my JVC 26inch color CRT T.V.. It was quite a challenge as much of my repair work with power supplies had been with the old buky linear type. JVC had very good documentation on their web site in the theory of how the switch mode power supply worked. The problem I was having was random shutting down and not being able to power up. After blowing a few modular type regulators and learning to respect the rectified 300vdc from mains voltage of the hot side, I was able to correct the problem through the replacement of the TL431 and it’s optical coupler. The TL431was a mystery and the only information I was able to find on it was that it was a programmable Zener. You have now solved that mystery for me my friend and I am very grateful to you. Also I would like to mention your video on the SDC2921 pwm 16 pin controller was of great value and how critical it monitored the 3.3v, 12v and 5 volt ATX power supply. I was not aware of the need for all three voltages to be present and operating normal within their ranges unlike the SMPS in modern day Flat Screen SMPS where emphasis is on the +5v standby. Take care my friend as your videos are invaluable.

[@josephbuganski8066]

THE BEST TL431 EXPLANATION ON THE INTERNET!!!!!!!!!!!!!!!!!!!!!!!!

[@HaseebElectronics]

it is my pleasure that you enjoyed my efforts

[@viswanathanramakrishnan7613]

Really I had missed a tutor like you when I had electronic course. Fantastic explanation with practical circuit. My salute with reverence to your approach in coaching.

[@HaseebElectronics]

it is my pleasure

[@romerovalin2635]

I love this video because it is in English language, ive learned a lot from this. Thank you sir. 🙏👍💐

[@viswanathanramakrishnan7613]

Always Mr. Hasseb's electronics explanations with practical circuits will be so informative. I love to watch his videos to enrich my faded knowledge on electronics. Thanks a lot for sharing the wisdom.

[@HaseebElectronics]

So nice of you. best regards for your golden words

[@michaelmccloy9466]

I really appreciate the very clear explanation of this circuit, I was a little confused by the title as I had just been watching another video on a TLV431 shunt, they did not mention it being a Zener, but it seems that there are two chips with similar names and similar functions. As I am a complete newbie in electronics, please forgive if this is obvious to others.

[@topannurhakim]

matur nuwun pak haseeb, panjenengan pinter banget, gelem ngajari,semoga dapat pahala yang banyak pak, terima kasih pak Haseeb, Anda pandai sekali , mau mengajarkan, JAZAKUMULLAH KHOYRON

[@danielg2]

Perfect! you are connecting dots I never realized before, thank you for sharing your knowledge with us!

[@gauripartapshanker9197]

Thank you so much. You set this topic in my mind forever. The calculation of reference voltage set in my mind forever. Thank you so much.

[@almightygod1023]

U ARETEACHING US IN A SCIENTIFIC WAY AND I AM VERY HAPPY WITH UR LECTURE.

[@lucasrocha4329]

I solved a smps issue with Haseeb . My power supply had 24v, 12v and 5v output. But, only 5v was right. The others were 29.8v and 14.9v. Thank you.

[@HaseebElectronics]

Wow that's awesome

[@abdraheem2171]

I also spent a lot of time learning about this and I got a clear idea from your video God bless you and your family

[@HaseebElectronics]

it is my pleasure

[@aliduadam2761]

You are the best KZbinr in pure electronics,infact your language is very clear with vivid explanation,after you explain no question is left.i have combed tru the Internet you are the best.mashallah.

[@HaseebElectronics]

It's my pleasure please accept my best regards for your valuable appreciation

[@asdbabel4913]

بارك الله فيك وامنيتي ان يكون شرحك باللغة العربية. تعجبني بشروحاتك مدعومة بالحسابات الرياضية وهذا هو الدليل القاطع.

[@HETRM]

explained with great patience and practical demonstration 🙏🙏

[@HETRM]

dear sir, i was going through few smps feedback circuits , they have different values of resistance for the divider for ex.12v10a smps has Rt of 28k and 24v6a smps has Rt of only 12k.why so?

[@rmjnm]

I really like the way you explain things, it simply leaves us with no doubt with the topics. Thanks for your support.

[@kanavsharma3058]

Thanks sir, one of the best video on internet for TL431 complete information, Keep up the good work🙂

[@HaseebElectronics]

special thanks and best regards

[@Aualas]

This video is the best explanition about to tl431 that i saw .Thank you very much!!

[@aliduadam2761]

U always teach the topics and question we have always be looking for.infact u clear the mysteries of electronics.jazaakallahu hairan

[@HaseebElectronics]

it is my pleasure best regards

[@khanlalavlogs]

Detailed oriented video shared. Masha Allah ur every video is very useful.

[@ardhi1269]

Your English is really good man Also your explanation is easy to understand

[@tyronearendse1722]

Thank you for sharing your knowledge and experience and taking your time to make videos in english as well, I appreciate it a lot

[@tyronearendse1722]

@@HaseebElectronics thank you

[@noor689]

Thank you so much brother.. Apki tamam videos zabrdast hain aur bht mufeed hai khas kr mai ne bht faida uthaya hai.. Mai apki mazeeed aisy behtareen videos ka muntazir hu Allah taala apko is ka ajr e azeem ataa farmaye aameen ❤️❤️❤️

[@HaseebElectronics]

Aameen Jaaak Allah khair aap mera urdu channel (haseeb Electronics Urdu) bhi check karein, wahaan meri sabhi videos urdu language mein hoti hein

[@anwarhusan9172]

Mashaallah very very informative video sir i have seen much video but your video / information is different thank you very much Mashaallah you have good knowledge continue these type video your video is very helpfull

[@jaimeizquierdo1168]

THANK YOU VERY MUCH I ENJOY WATCHING YOUR VIDEOS YOU ARE AMAZING ELECTRONIC TEACHER.

[@HaseebElectronics]

You are very welcome

[@netrapalsinghprjapati1935]

Sir, your way of teaching is very good I am satisfied thank you

[@muhammadishtiaq24]

Excellent thanks for sharing this informative video keep sharing

[@hichamhicham9041]

Mr HASEEB excelent video best explainnig of 431 zener reference. Thanks my friend.

[@mustaphabenali4896]

Thank you brother, may Allah reward you for the explanation🤲🤲🤲🤲🤲🤲🤲🤲

[@HaseebElectronics]

thanks a lot dear brother اللہ یسلمک رمضان مبارک

[@WithEmanFatima]

MasahAllah bhot umada view's aye hein dear brother eis video par MasahAllah kam walo khale yeh video kaam ki hwe gae MasahAllah

[@WithEmanFatima]

@@HaseebElectronics thanks very much

[@janasmeal7916]

Great sharing ma sha Allah 👍

[@ghamor7590]

و عليكم السلام و رحمة الله و بركاته Good explanation thank you very much

[@HaseebElectronics]

best regards and special thanks

[@fakharnaqvi2644]

Very nice! Ashraf Sahib Allah will give you his reward inshallah.

[@GAMENIX1]

Professor, you have no replacement, you are number 1

[@HaseebElectronics]

thanks a lot for your valuable words. please accept my best regards

[@rosszzzz]

You are doing great job.

[@jimmycollege3851]

excellent still better if u went over the other side or explained how it can be used as comparator thank you for explaining the potentiometer cct

[@CityfoodSecrat]

Video is soo informative and knowledgeable

[@samiafazal]

always superb informative video

[@AmnaKitchen]

Great VDO WD accurate information 👍

[@sundaravadivelums7661]

May god bless you sir.Long live sir.nothing else to say

[@HaseebElectronics]

please accept my best regards

[@dilippatel4994]

Really very informative video for TL431 ever....

[@Electronics-n2w]

Thanks sir very nice explanation I am learning from you

[@sukhbirrana9779]

Sir, You are genious. The best explanation ever I have observed on SMPS. WITH REGARDS ER S S RANA

[@nihatkosova8436]

Thnaks for many many information. Essalamün Aleykum from İstanbul

[@HaseebElectronics]

Thanks and welcome

[@HaseebElectronics]

wa alaikum salam dear brother

[@feebyewok]

Waalaikumsalam brother Salut dengan pengetahuan yang anda miliki

[@cookwithaditi3077]

Sir you are best teacher, I selut to you

[@zainElect01]

wow it is fantastic and technical work. thanks for sharing

[@totbenru]

For so many years, it has always baffled me how they use 431s (a Voltage Reference) to directly regulate output voltage of an SMPS. I never knew that they could function as a voltage comparator until I watched this video. Thank you so much. I have a question though. Since the 431 turns the Optocoupler "hard" on or off when reaching vRef, how does the SMPS not oscillate in its voltage regulation?

[@HaseebElectronics]

Best regards When TL431 pin 1 (reference pin) at 2.5 volt with respect to secondary ground (it is done by voltage divider network) Then TL431 will produce 1.3 volt with respect to +dc voltage of secondary. And a current limiting resistance is connected from +ve rail and optocoupler which is connected to pin 3 of tl431 (output pin) So out of 1.3 volt, optocoupler will drop 1.1 volt and 0.2 volt across current limit resistor When optocoupler led will activate, it will conduct the output transistor, which might be switch +volts for amps controller as vcc voltage Or it may switch offset ground level from 0 volt to 2.5 volt as feedback voltage Depending on feedback or controlled vcc Voltage the amps controller will adjust it's switching

[@userlevel61]

@@HaseebElectronics How to choose the current limiting resistor of the optocoupler?

[@josephineprimo4395]

Clear and very explained..thank you very much

[@HaseebElectronics]

You are welcome!

[@MicrosiMe]

Great explanation, but you must make another video on the TL431 current and how it affects the resistors values, and as you can see you have almost fixed resistors values

[@roomithegamer2499]

Superb you explained it so well so helpful easy to understand good job

[@barrahonlinequran]

Very good informative Electronic Idea video, stay connected dear brother.

[@baygidhasan]

its a vary informative video.love this.want see more electrinics calculation type video in future. Thanks.

[@rogerschelling5668]

Thanks for this video. So helpful to understand feedback with that Zener I see used on appliance inverter supply boards.

[@HaseebElectronics]

welcome and special thanks. I am happy that my efforts are fruitful please accept my best regards

[@bitdiddle1]

Kirchhoff's current law states that the current flowing into a node must be equal to the current flowing out of it. Applied to the VRef node, that gives (VOut - VRef)/R1 = VRef/R2 + IRef. That's one equation with two unknows, R1 and R2, so we are free to choose one of them. Set R2 = 1250 ohms, then VRef/R2 = 2.5V/1250 ohms = 2 mA is the current through R2. That current plus IRef, chosen to be 8 mA, sum to 10 mA through R1. The value of R1 is then determined by the choice of VOut. For VOut = 5V, (VOut - VRef)/R1 = 10 mA gives R1 = 2.5V / 10 mA = 250 ohms. For VOut = 6.3V, (VOut - VRef)/R1 = 10 mA gives R1 = 3.8V / 10 mA = 380 ohms. I think with your choice of resistor values, the TL431 reference pin draws negligible current (datasheet says it can go all the way down to zero).

[@MrTasniem]

Thank you, Jazaka ALLAH Khir

[@muhammadyounas6110]

Excellent brother, May Allah live you long & keep smiling

[@kingmoussa9443]

You are the boss hasseb

[@خالدباشميل-ب9و]

I don't know how can I explain for great thank for your lesson it very beautiful

[@HaseebElectronics]

You are very welcome. best regards

[@HarlavanisPanagiotis]

Excellent and very informative video dear friend, have a happy time!!!

[@educationkorner264]

You are true engineer

[@HaseebElectronics]

thanks a lot

[@pdanayal]

Very good and nicely explained.liked it your vlog.

[@HaseebElectronics]

Thank you so much 🙂

[@riloariichoariicho884]

As always I learned new ideas again in this video.thanks

[@EuanneHyunaRosas]

this interesting tutorial my friend thank you for teaching us.

[@user-pq5tz5pn4g]

السلام عليكم ورحمه الله بتوفق ونجاح أخي

[@nimalvithanage3303]

Thank you very much. Very good explanation.

[@HaseebElectronics]

best regards

[@Thomas1980]

very beautiful video. Greetings from Switzerland

[@koshishekasha103k]

Very helpful video uploaded 158 my friend

[@PakistaniFood1168]

Good Sharing MashaAllah 👍💕💕

[@CARLOSFRANCO1000]

Excellent topic my dear friend Haseeb. congratulations. 🎨🎼🎸🎻

[@LifewithMano]

A lot of info u have MASHALLAH 👍❤

[@giorgostexnikos6976]

excellent explanation.thenk you for this a m a z i n g video

[@ShineSakshi]

It's another amazing job of yours... Absolutely amazing, helpful.... My lots of wishes for more fantastic uploads like that 👍

[@uniquetravelandbeauty7026]

great technical skills keep going

[@t1d100]

Awesome video! Thank you! Please check my understanding... If the PSU has a TL431 to fix its output voltage and I want to make the output to be variable, I must set up the the zener reference as follows... 1) R1 will be a potentiometer and R2 will be of a fixed value, to maintain the zener;s minimum amperage requirement. 2) As the minimum zener output voltage is 2.5 volts and the zener requires say 10mA, R2 = 2.5V/0.01A=250 Ohms. 3) Let's say the maximum voltage that the power supply can output, before the transformer starts singing, is 18 volts. R1 would equal (18V_R1V - 2.5_R2V) x (100_TL431MaxmA - 10_TL431MinmA) = 16.5V x 0.09A = A potentiometer of 0 to 183.33 Ohms, configured as a Variable Resistor. Do I have that correctly? Or, do I misunderstand the way the TL431 manages amperage? Thank you for your help. Edit: And, I must remember to increase the voltage rating of the output smoothing capacitor(s) to at least 18 volts, 25 to 35 volts would be better.

[@electroFizou]

18v- 2.5=15.5v .not 16.5 .you made a mistake when calculating vr1

[@wardachannel571]

very good work keep it up and full view from us stay blessed

[@udhayakumara4033]

Everything is Ok, but the Iref is totally wrong. Typical TL431 reference input current will be in the range less than 10 micro ampere, not milli ampere. You should check this. So putting a 625 ohms resistor across 5V supply is totally non sense and it will give you unnecessary power loss and also it reduce the filtering efficiency of the output capacitor. R1=R2= 4.7K is good enough and the circuit will work just fine. Other than, its very simple innocent programmable reference to design and to explain.

[@snhongo1]

You are Very intelligent 👌 thanks for a great video

[@HaseebElectronics]

best regards and special thanks

[@ReenAisal]

Quite informative and educating upload thanks for sharing stay blessed and safe ameen amd stay connected

[@Foladstudio2023]

Thanks alat brother very clear explain

[@HaseebElectronics]

Thanks and welcome

[@PlayWithRida]

Asamu Aleikum! You're doing great job Haseeb!

[@nayabartgallery9326]

nice video it was very informative stay connected

[@carolinediyandvlog]

Witaj przyjacielu kolejny super filmik pozdrawiam serdecznie 😄

[@Crystalservices]

Thanks for your Informative video.

[@HaseebElectronics]

It is my pleasure 💕

[@nikmuusa8118]

assalamualaikum...good info,salam from malaysia

[@ahmedabdelrahman3712]

very good explanation with practical experiment. two points confused me: 1-you used the convention IREF to express the current passing the series resistors combination R1-R2,in the data sheet iREF is expressed as the current entering the reference pin and it's in microamperes. 2-how can i select the current range i will work with?

[@SubKaChannel]

222 with beautiful video ke saath saath give you good for that

[@farihabaloch4805]

It's a great sharing ✌️👍👌

[@nabilounabilou2119]

You guys are simply amazing!

[@FunnySurpriseToys]

Hey Friend! Thank you very much! Like #4

[@MadihaKhawaja]

MashaAllah really informative Like frm 🇸🇦 Stay blessed

[@usharani4561]

lk#118 gudmorning brother Informative video Still watching ..till🙏🙏🙏🙏☝️

[@Dr.QaisarAbbas99]

nice work dear bro thanks for sharing stay blessed

[@PakistanipardesiBhaiFrankfurt]

Good Sharing 👍👌💞 lk

[@electropath678]

Brilliant. ..nice explanation.

[@candabi]

Amazing as allways. Thank you !!

[@HaseebElectronics]

thanks a lot. best regards

[@مطبخماماحبيبتي]

Nice video big like great work keep it up 👍👍👍👈🙋‍♀️🙏🌷🌹🤲👈👀👉

[@cthoadmin7458]

mr. Haseeb, this is brilliant! What better way to learn about SMPS than experimenting with the components? Tell me, would this be a good way to test the low voltage side of a SMPS: Suppose you had a faulty 12 volt PSU. Could you apply 12 volts to the output without powering on the SMPS, then look at the voltage across R1 and R2 and the voltage reference, then measure the voltage across the input to the opto isolator when the applied voltage is less than 12 volts? If the output circuit feedback loop is working correctly there will be a voltage drop across the optoisolator, and the resistance on the phototransistor side will go down, in other words the photo transistor switches on...

[@ibrahimtamemy8828]

احسنت شرح واضح Keep up the good work 👍