How to design and build an LED constant current source using a Zener Diode

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in this video we look at a Classic Circuit You Should Know - The Zener biased LED driver. Here is a link to the calculator: www.pcbheaven.com/drcalculus/i...
In this circuit, the base current is fixed by the Zener diode. If the base current is fixed, the emitter current is also fixed. So small changes in supply voltage will have very little effect on the LED.
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Опубликовано:

27 ноя 2021

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Комментарии : 73

@charlescartwright6367 2 года назад

Aloha, your calculations were for a 3.2V zener and you used a 3.3V zener, take that with the tolerance of the zener I think you were smack on. Thanks for sharing most of us do appreciate what you do.

@TRONMAGNUM2099 2 года назад

TY for the breadboard closeup. Makes all the difference in the world when I am trying to repeat these circuits at home.

@learnelectronics 2 года назад

Thanks, I'm trying to up my production value

@melplishka5978 2 года назад

Glad too see your humour Comin back brother. I laughed my ass off lol

@t1d100 2 года назад

Thank you for your efforts to teach us! This was a better video production = You drew the schematic at the beginning = Yea! One small addition would make it even better = Show how the power moved through the circuit = For a NPN transistor, power moves through Base to Emitter. You did state that, but drawing a line of the path would add emphasis. All together, a better video and teaching = Atta-boy!

@khuongathebounga4141 2 года назад

Thanks for the detailed video and lesson. Really appreciate the hard work you do.

@bblod4896 2 года назад

One day, I sat at the bench building jumpers for my breadboard, then I saw your vertical Dupont jumpers🤯😢 Thanks for the video Paul. ☮️✌️

@bwselectronic 2 года назад

I'll be honest. I watch or at least listen if I'm working, but I won't fully comprehend it until I sit down with the video and do the project while I'm watching you do the project. But I at least have had some of the information get stuck in my head. This will be a future experiment when I have time

@johnjoyce 2 года назад

Your calm but fired up intro is full ass in use. Thanks for another great permanent lesson.

@michaelpadovani9566 2 года назад

I have a bunch of Zeners, now it's time to put them to good use! Appreciate all these tutorials.

@steveboyd314 2 года назад

As always, you're a natural teacher. I feel the need to speak up, though. In future could we possibly start using code words for certain things that just aren't good visuals? Say, "I'm putting my whole radish into the production of this video" or "just so you don't chew my orange out" just saying... 🤣 Thanks for your constant sharing, Paul. Your teachings are a privilege to watch.

@bwselectronic 2 года назад

So if I got it right, you think he should use the polititicaly constipated way?🤣🤣

@donhiscock6933 2 года назад

Grate video Paul I really appreciate the work you do to bring us these videos. Don't take any crap from anyone on hear. Your doing a great job.

@mufeedco 2 года назад

I learned so many things watching your videos. Thank you.

@inspectormills3290 2 года назад

Exactly the type of electronics video I was looking for. Thanks

@simonowen488 2 года назад

Nice comeback and good on you for it.

@anokhautomation4453 2 года назад

Nice experiment and tutorial.thank for sharing your great knowledge.

@gartmorn 2 года назад

Great wee classic circuit. Easy maths is always good, Hope the snow isn't too deep? We had our first peppering of snow yesterday but all gone again today! 🤣

@learnelectronics 2 года назад

All melted here too

@anurasenarathna1703 2 года назад

Like your series "Classic Circuit You Should Know". Thank you.

@nicksanto882 2 года назад

I didn’t think this was slow at all (half fast)…. Great stuff at full speed ahead!!! Keep up the great work!!! Thanks again!!!

@cndbrn7975 2 года назад

Thanks bro, I was just looking for a low constant current circuit. Don't pay no mind to the haters.

@bobpaugh6725 2 года назад

Great video. Thanks.

@bertbrecht7540 2 года назад

I am now very interested in Zener diodes and how the heck plugging its anode into negative could do something so unexpected. Time to watch reverse bias videos. Thank you!

@jumboegg5845 2 года назад

I think its the main way zener diodes are used, we use the breakdown voltage to get simple voltage regulation

@tamarabarnett9869 Год назад

Love your videos.

@ericsumma7654 8 месяцев назад

I enjoy theknowledge refresher, no matter which side of your as.... you use. Thanks again.

@sinjhguddu4974 2 года назад

Very cool and very simple.

@GM-vk8jw 2 года назад

Zener diodes are amazing. The knee of the Zener is pretty interesting. Transistors are the work horses of a ton of circuits. This was a whole assed video by a bad ass You Tube educator that posts this stuff on here for entertainment and improvement.

@killer2point057 2 года назад

Great stuff... Thanks again my friend

@MrDoneboy 2 года назад

I hope, as always...That is going your way, Paul!

@varmint243davev7 2 года назад

Thank You !

@PerrynBecky 2 года назад

A great intro that made me chuckle. "I will be using my entire ass in this production, and it is substantial". Now on to the presentation. :-D

@richspillman4191 2 года назад

That was great, a basic I should have known.

@tariqal-khawaldah590 2 года назад

Thank you so much

@BrucesWorldofStuff 2 года назад

Thanks Paul for the laugh and I'm glad we got the whole thing this time... ROTF Also thank for taking the time to teach us. LLAP

@adamv242 2 года назад

Class in session! Pay attention, take notes.

@Johadart 2 года назад

Cheers for the great explanations, you simplify it for everyone. 🤙🏼🤙🏼🇦🇺🇦🇺 P.s you still got a nice toosh lol 🍻

@weerobot 2 года назад

Cool Classics...

@KevinDC5 2 года назад

Another great explanation and video tutorial, but now I’ve got to put in a request. Please do a “High Current” led driver circuit sometime please sir? I have a bunch of these Cob LED spotlight boards with 24 leds in parallel. The original circuit I got them from had an inductor and a couple of capacitors and operated on a single cell lion battery. I try and power them from battery alone and they get just a fraction brighter but ALOT hotter so they’re definitely sucking the current. So I figure it’s not a boost circuit, it must be some sort of RC oscillator perhaps allowing the battery voltage to get pulsed at high speed as a means to controlling the current through them. 🤷🏼‍♂️

@opalprestonshirley1700 2 года назад

And yes folks it works!!!

@PATRIK67KALLBACK 2 года назад

Great informative Video! However I come with a challenge. How would you design a circuit with constat light (with the help of e.g. photo diode)?

@LaplacianFourier 2 года назад

How would you integrate a microcontroller to this for controls and PWM dimming? Thank you.

@aduedc 2 года назад

You can use n-channel Jfet and get rid of zener and R1. Just connect the gate to ground.

@ed-jf3xh 2 года назад

Good job. Have you shown the 2 xstr/2 rstr current limiter yet?

@learnelectronics 2 года назад

Not yet

@johnangel1512 2 года назад

so how do I control current to stop burning out the resistor with a 5v 20A power supply (am running led strips but want to tap of same supply to run timer and maybe 8 5mm leds, without putting another power supply in, space is limited ?

@XPFTP 2 года назад

be cool to see a regen built and explained how and why things work. just sayin.. could be a few 3 or 5 videos. some sort of band selector. so as to cover vlf to hf

@zaccagnagalileicorsiserali 2 года назад

Why do you let to work the BJT in Voltage and not in current?

@electronic7979 2 года назад

👍

@Joso997 2 года назад

Can you achive that with 220VAC ?

@bwselectronic 2 года назад

I'm glad you're going into it all assed. It's better than being jackassed like some of the people who complain about everything. 😎

@ariedekker7350 2 года назад

Thank you for making this video and letting it see me. pe1krx

@lookupverazhou8599 7 месяцев назад

What is the significance of a transistor in maintaining a constant current? Is there a way to maintain a constant current without a transistor?

@stlo0309 2 года назад

0:43 lol

@johnm2012 2 года назад

How did you choose the values of the two resistors?

@learnelectronics 2 года назад

Look in the description man, there is a link to the calculator.

@bblod4896 2 года назад

Yes, a full moon video production 😆

@FritsvanDoorn 2 года назад

Its been more than 35 years ago that I learned. But, isn't it that the constant current is ocer Re? The rest of the voltage is divided over CE and the LED and therefore the current changes through the LED when the voltage changes? I am a bit confused.

@hadireg 2 года назад

👍👍TY

@jameskidd7906 2 года назад

A simple question (not linked to this tuto) how can i get 3v AC from 6 v AC output transformer without hack the transformer itself ? Any help are welcom tanks a lot

@mikebond6328 2 года назад

The simpler thing to do is look for a transformer that will give you the desired output with the desired input.

@waynegram8907 2 года назад

You didn't show how you came up with the resistor values 470ohm for RB and 220ohm for RE, how did you come up with those values?

@learnelectronics 2 года назад

Use the calculator in the description

@joemitchell5243 Год назад

I’m trying to understand this. I see that the emmiter has a resistor and the led doesn’t. I’m guessing that it’s because of ohms law as to why the led doesn’t need its own resistor?