Constant Current Sources (Interactive!) - Simply Electronics Basics 9

What are Constant Current Sources? Find out how they work and why they are useful. Try the circuit!: goo.gl/BRpqnD
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[@kushh4204]

what was left on my mind towards the end of this video is, what is considered a constant current source. Or in other words, how to i get/make a constant current source... i understand what constant current sources are capable of doing and how they are useful. but the one thing this video was missing was an example of what a constant current source can be.. like when you talked about dc power.. you mentioned a battery.. which then if i decided to try out a dc power circuit experiment, i know exactly what components i would need.. but with this video i dont know what component i need to make a constant current source. but still a great video dont get me wrong

[@jethrowu27]

search for current transformer

[@giri6809]

A transistor in saturation condition can act as a constant current source so the component constant current source in the video can be replaced by a transistor

[@jsanjay5513]

The simplest constant current source would be a BJT. A current transformer wouldn’t exactly work the same without rectification and filtering, plus it isn’t practical for this application. Good question though!

[@sonajero25]

you can buy a constant current driver the same way that you would buy a battery. They are pretty common components.

[@sylkelster]

Without having to make anything, benchtop power supplies with voltage and current control knobs and set to run in constant current mode will be the most efficient current source for experiments. A ballast used in fluorescent lighting fixtures is a current source. A specifically sized transformer can be used as a current source. Resistors are current control devices.

[@Iosens]

I don't understand all the positive comments below. This is not how this works: Different color LEDs will never work in parallel as shown (probably not even same color) - should have done that with Resistors or possibly light bulbs... Just try it on your bread board... (This only works here because the simulation software is set so all diodes have the same voltage, which is not happening in real life).

[@Usnveteranstacker]

Someone’s a Debbie downer

[@qt1qg]

Seems like trap to make people comment on video, there is no way a channel creator could made such mistake for real

[@HazeAnderson]

Wow, I have seen a lot of vids on constant current sources and this is the first one that I actually understood. My disconnect was thinking the voltage stayed the same. I think a LOT of trained EE overlook these otherwise "should be obvious" clues that help us newbies stay on track. Cheers!

[@RX7GSLSEowner]

Cool video. However, what forms does a constant current source come in? I can only think of a variable power supply that allows you to vary the supplied voltage or current. Seems like a laboratory thing. I'm guessing that you'd use some current limiter in a circuit, supply it with slightly more than it needs, then you get your constant current source, much like an LDO?

[@florabee9283]

Should the LEDs be in series rather than parallel when one intends the same current in each of the LEDs due to different colored LEDs having different voltage drops for a given current?

[@qt1qg]

Red LED would light up first and burn out in seconds(half a minute at most), if it fails open all other will burn out subsequently(though blue one may stay lit depending on it's voltage drop, depending on maximum voltage of constant current source), if it fails short it would either way have voltage drop of less then 1 volt and no other LED will light up

[@onothodox]

What happens when one of the leds break? Since its set at 80mA, would it destroy the others by giving it more current than the amount it needs?

[@oddlyspecific1572]

That's my question as well, if you get a chance to explain.

[@sanderverhage5148]

You are right. Therefore it's not smart to connect the LEDs in parallel. When the LEDs are connected in series on a current source, you are sure all leds pass the same current. Even if the forward voltage of the leds is different. This is most likely for leds with different colors. By the way,never connect leds directly to a voltage source. A lead has no linear relation between voltage and current. Once the voltage is slightly larger as the forward voltage of the led, current rapidly increases. So with manufacturing deviations, temperature diverenses,... it's impossible to maintain a steady current through the led, using a voltage source without resistor to limit the current.

[@AlexandreKandalintsev]

Only matched diodes can be connected in parallel. Otherwise they won't share current equally. No way diodes of different color can be connected this way. The diode with lowest forward voltage will take all the current.

[@fastlingo]

yes, and also you cannot even connect one diode to a voltage source like that, unless you make sure that the voltage source is current limited, otherwise you will burn the diode as its current does not increase linearly, itwill draw more and more current with just a little increase in voltage over it's voltage threshold.

[@martinmartinmartin2996]

You are almost right : the V-I curve of R LED is radically different from a G LED which is radically different from a B LED... see lednique.com/current-voltage-relationships/iv-curves/ I would guess that a 60 ma constant current source would be divide amongst the diodes as I]red ~46ma ; I]G ~ 12ma ; I]B ~ 2ma further the current will continually divide differently as real LED heat up .

[@helixalgorithm3160]

This problem is irrelevant here, but in general you are 100% right

[@johnnytacokleinschmidt515]

I guess they could have chosen incandescent lamps.

[@garokejelian565]

it took me the whole day to understand it, but with ur explaine made everything easy :)

[@LtMewS]

Liked this video.. Question - which one is better - 1.using resistance to limit the voltage to light Led ..so specific current is passed. 2. Using constant current to allow specific current in the led... And tell in which cases I should use these two..

[@vyns5896]

Can I ask why this video shows the current flowing from + to -, yet previous videos showed if flowing from - to +.

[@edisonfajardo2148]

what software your are using sir in demo?

[@nieuwegeljo5645]

So far I very much enjoy your video's because of the simulations you show and the clear explanations! I have been taught the very basics many years ago. Thanks very much!!

[@anslemmacalintal-om9vc]

What are the names of application I can use to perform this practical cos I really understood you and would love to give this a try to confirm my understanding

[@andrewholz1414]

So the constant current power source also provides the voltage right? No need to add a battery? I'm guessing because it is a power source (P=IV) and that the I component is fixed?

[@theaussiemanhole2193]

What you are doing just keeps getting better.

[@Drone360pilot]

very interesting subject , thank you for this video. Can you pls give a sample of active component that can be used as a current supplier. Thank you

[@merseytrainz]

Another Great instructional Video. Thank you

[@SimplyElectronicsOfficial]

You're Welcome! Another coming very shortly :)

[@saveplanet3977]

Explained the basic concept so nicely

[@epartsvn]

Great solution

[@wiltanschannel82]

Hi, I'm using the same simulator app. Im not sure how to correctly model transistor and MOSFET to simulate close to real device. I appreciate you make a video how to set parameter value for it.

[@jaidmulla9550]

Thankyou so much sir I easily understand the constant of current and voltage..😊

[@RaviKumar-xx7gi]

Hi I have made the circuit of LM317 on bread board. I am generating a constant current of 100mA. The input to the regulator is 3.3vdc. 100mA constant current is fed to a resistor of 100 ohms. I should measure a voltage across resistor of =10mA x 100= 1000mV=> 1V, but the voltage across the resistor I am measuring is 3.3vdc. why so? I want to use the constant current source to find the unknown resistor using current and voltage How can I do this?

[@andrewholz1414]

at 3:42 , is it correct that the power being supplied to the circuit is 240 W? (assuming ideal conductors/resistors/etc.)

[@charlesklein7232]

I CAN CHANGE VOLTAGE WITH MORE BATTERY, BUT WHAT ABOUT CURRENT? a larger battery would i suppose have more current? is their a rating to how much the battery can supply? their are some rechargeable battery that say how much current and how long they can last i think.

[@princemishkin1601]

Super explanation

[@memeagain4106]

in your other video you show the electrons flowing the other way round.. i thought the flow was from negative to positive?..

[@grevedj]

me me again thought that too

[@daymienrogue2530]

EveryCircuit program allows you to show "electron" flow or "Conventional" flow . This is because at one time it was believed that electrons would flow from Positive to Negative. So all schematics and circuits drawings were arranged that way and it became sort of a "Standard". So since so many schematics were drawn that way it is still used that way when drawing circuit diagrams. Some programs allow you to switch between the two just for personal preference. In all reality it does not matter which way it shows that it flows in these Circuit Simulators because the end result is the same. As long as the circuit is closed electrons will flow no matter which way they are shown. Its just personal preference mostly. Depends on how you were taught.

[@mentis72]

Hi How do i test if a constant current source is working and not the LED without having purchase another LED to test it.

[@Melox-gt2oy]

Is it possible to power an LED which draws 20mA und has a max Vf of 3V with a 3V powersupply? Since there is no voltage left for a resistor, will the LED draw exactly 20mA? Do you always have to power an LED with more than its Vf to have enought volts for a resistor to regulate the current?

[@kibromkifle2860]

Buddy appreciate you what you are doing. It's really helpful, and would you mind if you post more videos about transistors and higher level circuits thanks.

[@NicCorbett]

In the both circuits, why is current flowing from positive to negative?

[@TriplekilzTk1]

That is the convention. When Benjamin Franklin discovered electricity, he had no way of knowing in which direction electricity (electrons) flowed so he arbitrarily chose positive-negative. Everyone just went with it. When we later realized this wasn't the case, rather than change the convention, we just stuck to it for convenience.

[@rosshollinger8097]

@@TriplekilzTk1 Yes, but in his previous videos the current was running in the "correct" fashion, neg to pos. So why the change?

[@TriplekilzTk1]

@@rosshollinger8097 Perhaps so that the people that watch the video aren't confused when they find that a majority of engineers follow the convention. In any case, he should have provided an explanation.

[@alqamarsIndustry]

What is device example of current source ?

[@fklotaloi]

Very very informative ..I did not understand ths CC terminology , I read online , bt now I m clear coz of th exp tht explained. Thanks a lot uploader. :-D

[@aibasei3254]

hi pls can u give sm examples of current sources ? can i assume that battery is the current source

[@MrBobWareham]

I loved the video thank you but want to make a circuit to control constant voltage of 27 volts dc with a constant current of 2ma dc so in your demonstrater can you show such a circuit and how it works, thanks for any help Bob

[@hichamtassi1753]

Hello, very nice video ! i did the same, i used 1.5 Ohm to have an output of max 1A, but when i plug a load to my 12v lamp bulb, the voltage drops to 4v, is it normal ? many thanks.

[@ankitpatle1996]

Good videos... Keep it up... 👍👍👍 It would be great if you show us how to make some constant current circuits

[@SimplyElectronicsOfficial]

You bet I will :)

[@ankitpatle1996]

+Simply Electronics Great... Wating for it... 👍👍👍😃

[@BariumCobaltNitrog3n]

@@ankitpatle1996 5 years later. You can stop waiting, the last video was 4 years ago with no more on cc circuits.

[@80kg]

Good video. BTW, what is the software you used in design circuits? Thank you.

[@EvenTheDogAgrees]

you imbecile

[@stavroshouiris]

Great video but I strongly disagree on your argument were since it's easier to use a current source that you should use one instead of a voltage source. Reason why is being that in a scenario where one of the four LED's burns out the other three start to get more current, then when another burns out you're left with two LED's that are running on 40 mAmps each, then when one of those burns out, you're left with the last standing LED which will be running on 80 mAmps which I assume would burn out at that point. My main argument is that you'd be decreasing the life span, I'd say stick to resistors because although there more time consuming they are worth the time.

[@harrisnawarangy7978]

But what about integrated circuits, which cannot handle the size of a resistors, there we can use constant current sources .

[@sonajero25]

the point is that when using constant current sources the LEDs are connected in series.

[@rajatkumardawn3216]

Is there any example of constant current source

[@joerivde]

How do you gain/create a constant current source?

[@lemontea2065]

Thanks a lot! Your videos are great! Simple and comprehensive. Is there a technical name for the “active component” which allows to control the current flow?

[@SimplyElectronicsOfficial]

Thank You! The active component would be something like a linear current regulator or switched-mode current regulation IC. Active components are "Active" because they rely on having a feedback loop so that they can monitor output and respond/compensate for any change.

[@vietluongtruong9496]

i have a question. What is the source is DC or AC ??

[@syRoboChe1]

Thank You for this great tutorial!

[@jakegill7796]

WHICH DIAGRAM SHOULD I USE FOR A 12V 30AMP CC?

[@johnpeter1002]

Very good explanation ❤

[@kakoinstalirati...6081]

Good bless you, you are doing something special did you know that ? , you are giving oportunity to those that wan ' t to change their education without taking expensive confusing courses. This is all they need. Thank you.

[@JERRY_ONG]

hello, when you add a LED to the constant current circuit, how can the volt changes to 2.95v

[@oscarpeters1351]

JERRY ONG ohms law, resistance (forward voltage of the led) in the led

[@DavidCAIRO7]

Hello, firstly I want to thank you alot for all these very helpful courses, Could you please help me to understand, why the current is 2.95 V (why this value) after adding a diode ? is there any equation to calculate this value ?

[@FriedEgg101]

Yes, ohms law equations. If you know the current and the resistance you can calculate the voltage. With any 2 of these variables you can calculate the third. In the circuit you're referring to we actually know the current and the voltage, but not the resistance of the diodes. So you'd have to work out the resistance of each diode to be able to calculate why the voltage dropped from 3V to 2.95V after adding a diode. Check out the first video in this playlist.

[@k17741]

This bothered me too so I did more research. The constant-current source must decrease voltage because adding a 4th diode *decreases* total resistance in the circuit. Resistance is calculated as: (resistivity * wire length) / area Adding a new diode increases the Area the current flows through, so resistance is effectively *decreased* in the circuit. Hence lower voltage required to keep the current constant.

[@rickyperdana7941]

can make constant current with potentiometer ?

[@civedm]

What program is that?

[@ecombusinessecombusiness6692]

Can I ask you what is the pc program you are using ?

[@Dennis-er8xc]

good job on explaining things. Thanks

[@inspiratex]

what are the examples of current sources

[@seshachary5580]

VERY EDUCATIVE, THANK YOU. REGARDS

[@demoncore7275]

how does it work in real life such as using the constant current source

[@shahidilhan3139]

but in the parallel circuit how many volts does each LED take?

[@SimplyElectronicsOfficial]

We are supplying 3 volts, so all the LEDS will be supplied with 3 Volts

[@vinodnadoni5047]

Which software is used to simulate?

[@naderhumood1199]

You're great Sir Thanks very much 👍

[@rahulmaurya3886]

Examples of constant current supplies??

[@dasgettopikachu7878]

But why does the voltage drop to 2.95V?

[@ANKITKUMAR-kc2zw]

Great video.Thanx

[@davemjsons]

great information..thanks

[@darshanrs399]

what makes constant current source

[@chiduralajeevankumar8775]

I have a doubt...why to be grounded...please clarify sir

[@oscarpeters1351]

Chidurala Jeevan kumar dont need to be grounded, because it goes directly back to the source in this diagram

[@yomum9404]

thanks

[@fododude]

Mmmm. Currant sauce!

[@rahulmaurya3886]

I just wanna make my own circuits soooooooooooooooo baaaadlly but I cant coz I exhausted the trial VERSION of every circuits. ANY alternatives to it??

[@oscarpeters1351]

Rahul Maurya icircuit

[@rahulmaurya3886]

@@oscarpeters1351 Thannkkkkk youuuu!!

[@TuanNguyen-pd5yo]

That Great. Thank you very much!

[@charlesklein7232]

after reading the statements by other people the only thing i can think of would be a power supply that allows you to control current. is that what your speaking about.

[@eletronicaparaohooby]

Awesome! contratulations! Whats is the software? thanks!!!

[@dougscott2408]

there it is again... electrons flowing from + to -... this messes with people when you did not tell us why?

[@glasserallen]

Wow you know your stuff, maybe you can help me with something, I bought a solar panel, NO battery, to go direct to dc/ac power inverter, which needs 12v dc to run, my solar panel does 22.5 v. so I bought a cheap china junk buck step down regulator, it worked at first, then it was fluctuating very badly, wasn't constant, & lost the ability to adjust it... 12v, which is what my dc/ac inverter needs, would a >>>>"Constant"

[@kardeef33317]

da man ,all solar panels will have a higher voltage with no load. If you have a 12V 100Watt solar panel, it will be 12V with. 100 watt load in full sunlight. My guess is that when the buck puts a load on the solar panel your voltage is dropping to 12v or lower and most buck converters need 3v to 5v more then what they are set to, so when the solar drops 12v under load the output from the buck will drop to 7v or turn off tben the voltage on tbe solar goes up the buck turns on and the voltage drops again causing it to cycle. Hope that helps.

[@ytolstoy]

cool thanks! would have been nice to show what it looks like also :)

[@ytolstoy]

Thanks. Btw, I really like your videos, simple, short, straight to the point! Keep it up :)

[@MrLalochifrin]

nice

[@eldityasubekti1472]

what this software simulator?

[@Yousouf88]

thanks tooooooo much

[@CircaSriYak]

Hey, what kind of british accent do you have?

[@mokus8643]

thanks ..gud vid

[@SimplyElectronicsOfficial]

You're Welcome :)

[@niloyu105]

40sec. Ads completed 👍

[@SIGSEGV1337]

You sound like an alternate reality Paul Joseph Watson where he didn't become an insane ideologue and instead decided to do something productive with his life

[@deepakroy82]

how to make virtual videos

[@marufhasan9365]

he used a site called EveryCircuit.

[@deepakroy82]

thanks. could you plz tell me how to make the animtated current flowing presentation?

[@ifell3]

or you could run them in series ^^

[@sukhamaychowdhury]

did not understood diff

[@Enigma758]

Sorry, but there's so much wrong with this video, you really should take it down. I don't mean to be harsh, but as others in the comments have pointed out, you are spreading some serious misinformation.

[@pirateman1966]

Those LEDs do not exist. There is no such thing as Red, Green or Blue LEDs that operate at 3V. If you're gonna make shit up, make sure you tell the viewer. People who are learning the basics don't know that.

[@Enigma758]

That's just one problem with this video. Constant current drive is for LEDs in series, and if he insists on doing that, he still needs one resistor per LED. Even if the LEDs were the same as he states, that would still be true due to manufacturing differencs.

[@qt1qg]

It probably is a trap to instigate vicious commenting

[@johnconrad5487]

How is this a tutorial? he just sticks several LED's in parallel and has a current source feeding them. There is no guarantee that each gets the same current so this is a lie!!!!! the only way for each diode to get the same current is if they are in series. so he is bullshitting you people.

[@POLMAZURKA]

better yet ...show us on a real PS set-up..............

[@abbeed1]

thanks