Robotics and Electronics Tutorial - 10 - Building a Circuit

[Bloghreth]

FYI all of the current does still go through the LED. Current in series is the same. The reason you put a resistor in series with the LED is so there will be a Voltage drop. Power = VI, so because there will be a drop in voltage (due to the resistor), the power disapated by the LED will be less. If you had the LED hooked directly up then ALL of the power disaapated by the circuit would be through the LED and that could cause it to burn out.

[ixamraxi]

I think there is a lack of intermediate videos on the subject of LED's, Different colors have different voltage drops as well as different current ratings for ideal performance, and these differences should be taken into account when calculating a proper resistor value. Subtract the LED voltage drop from the supply voltage, and then divide the remaining voltage [which is the voltage drop across the resistor] by the ideal LED current, Rt = (Vt - Vled) / Iled.

[alaminopu10]

Hey! we are so much interested in this area. Can you please make more tutorial for us?

[JKTCGMV13]

If i was taking a formal class it would have taken a week to get to this point.

[HomoSapien2012]

As far as my knowledge, electrons flow from -ve to +ve, in this case u must place resistor on +v or cathode side(blace wire side), there is something really wrong with this experiment isn't it ?

[firerainstorm007]

yo man could u gimmi yo email id?

[TheMegalucian]

i have a question: why didn't you put a resistor on the negative part?

[Clobalize]

It leads to the positive end of the circuit.

(-) -> (+)

[steamisM50]

Positive = anode? no,I am pretty sure it is cathode.

[OCoptimusconvoy]

NO WAY! You do robotics too??!!!?!!?!?!?!??!

[TheHoho001]

@WhiteShadow1415 It makes no difference, the resistor can be on either side of the LED.

[princy917]

Bucky you are Dutch, I can tell

[Mrjameslat]

@princy917 dude who's obviously Alantian. or maybe alien. i'm not sure yet :P

[cuttyspark]

@KSHAUGER & @SummerGameProject.. In reality, no, it doesn't matter which side the resistor is on. The two components together make up a Series Circuit, and current is the same at all points, but voltage changes.

[orientalgolem]

Great tutorials. When will you show us how to build a Cylon? ;-)

[KSHAUGER1]

yea dumb ass u just showed them the wrong way to place a resistor on a led circuit from a battery power runs negative to positve so people you might see the led either blow up or burn out when you conect them all together

[SummerGameProject]

@KSHAUGER1 There is no right or wrong way to place a resistor in a circuit dip shit... This guy made the video perfectly, he may have forgot to specify the correct resistor to use, other than that it's perfect for noobs. So stfu, and watch. Maybe you'll learn something -_-

[KSHAUGER1]

@SummerGameProject i did take an electronic class dip shit and current flowing from a battery runs from negative to positve so you have to have the resistor on the negative side not on the positve so now why dont you take a class dip shit..................

[18iscoming4you]

@KSHAUGER1 Ohms law

[uttershock]

So, he IS NOT going to tell you what size resistor he used, no matter how many times you ask. There's always one little tiny part to every puzzle that get's lost and causes the puzzle to become trash and get thrown away. Just like this video. It ain't no good without all the parts. People assume everyone knows what they are thinking. Too many Barny's in the world. Everything becomes a waste. Hey! Great video..But useless without the resistor value! I ain't gonna blow up my LEDs.

[hovo327]

when you connect the alligator clips to the resistor, does it matter if you connect it to the negative or positive?

[Aaryan701]

Thanks a lot mate ur video helped me in understanding the concept of dat circuit,the way u explain was gr888,don knw abt othrs but i do get it .....thank again.

[Maloperverso]

How come he can touch the alligator clips without getting zapped by the voltage/current coming from the battery!?

[isionline]

@Maloperverso because its 9 volts

[1xDRCx]

when working with higher voltage, it's good to put some LED's in because they only allow current to flow in one direction, making it impossible for current to pass the wrong way

[listojay]

how about how do diodes make ac to dc video? and transistor can amplified volts and capacitor how!!! who what wher why when how pllllllllllllsssssssssss... 

[WOWNumansi]

Why do u use a PCB?

[djarnexus]

How do you know how much current/voltage a component can handle w/o being blown? Is it stated on the package err smm?

[merin344]

@crazeycane

I second this question. Can any one could throw some light on this?

[1xDRCx]

@crazeycane it doesn't really matter what resistor you use, any you could find in an electronics store have enough resistance to protect the LED, if you use a larger resistor(one that resists more current) it wont matter, it will just make the LED dimmer because less current is passing through, so any resistor should work.

[abnermioten]

@crazeycane you use a 470 ohm reistor

[Eldeeff]

@crazeycane He did. A few tuts ago.

[BackyardAmusement]

@crazeycane - For maximum life, the LED should run around 25milliamps. Knowing your voltage, 9v, and your amperage = .025amps, you can use ohms law to calculate R=V/I or 9/.025 = 360ohms

Hope that helped.

[TheHoho001]

@BackyardAmusement Actually an LED will have a voltage of aproximately 2V across it. So you need to do (9-2)/0.025=280Ω. Usually your calculation would be ok but when you connect like 4 LEDs in series then 360Ω would be too high.

[secretsather]

@TheHoho001 - Ah, you are correct. Thank you.

[zongivila]

@BackyardAmusement

u helped me out,thanx

[crazeycane]

what u didnt xplain is we know how to measure the resistor but wht size resistir we should use for this LED light.... So wht size resistor did u use?

[jerico211]

Sir, question, can i use a 12 volts battery in this kind of ciruit?

coz am thinking to replace my bulb ligh into a LED in my car.

[frostedlambs]

do you have a tutorial on welding?

[djarnexus]

@frostedlambs

do you mean soldering? Just asking, because for the context of this, soldering would come up first.

[Tspider4]

@debit...

It don't matter on what side the resistor is. And you are not wasting energy, your battery Will live longer if you let the led less bright with a resistor...

[debit256]

I have a Question. If the current runs from negative to positive than how does the resistor protect the LED? The current will flow to the LED first and than to the resistor from the way it is set up. Also, If you use a resistor to resist, lets say a 9 volts for 6 volts of current. Are you wasting the other 3 volts?

[adderek]

Some correction:

Resistor is used to LIMIT the current which goes through the circuit. LED has its own resistance - but it very depends on the voltage which vary over time when using battery or most other power supplies. So the same current that goes through resistor must go through the LED.

By the way - my son can make such a circuit and he is 2.5 years old... He is usually skipping the resistor part :D

[expertprogrammer]

Fuck you nigga.

A flashing led has it's own resistance anbd no you 2.5 year old son does not know how to read so he can't read bands.

[calvinator9111111111]

Hey guys, i have bought a r/c car, and im thinking about making myself a little project. My plan is to install two led's into the headlight slot on the car's body. I was jw, does it matter what resistor you use for the led? I assume the higher the resistance, the dimmer the led will light. So in that case, what value resistor would you honestly reccomend for me to use on my two led's that will be hooked up in series? Cheers :)

[cyberlord64]

depends on the power supply (your rc battery) and the led you will use. also will the leds be powered on once you turn your switch on or only when your car is moving? give us more details

[calvinator9111111111]

Im really not a boffin when it comes to electronics so bare with me lol. The car uses 4 x aa batterys. I will be connecting the leds in series. I want it so when i turn the car on by the switch already installed, the led lights will turn on. I have no idea what l.e.d s i will use, but with the given information, what would you reccomend? Cheers :)

[lleoleite]

nice tutorial, thanks !

[h333333333h]

Are you making tutorials for 10 year olds?

It is not robotics, i did this stuff when I was about 8...-.-...

Do REAL robotics or electronics...

[jpapgroup]

yhe i agree

[zanguretsu]

yeah for learning!!

[SiilyGuL]

y mus the resistor be cliped at the + and not the - ?

[briancastellanos]

Power Leaves from + and goes back via -. If it was connected to -, then it would slow down the power before it went into the battery. That would mean the LED would get too much power (9v vs 2.5v) and it would burn out.

[SiilyGuL]

but voltage leaves from - to + ,right ? like u said --9 "v " vs 2.5 "v "-- so shouldn't we be blocking the volt and not the power ? o.O

[fadenkreuze]

the 2.5v just means that there has to be that many volts present for the LED the light up.

[cyberlord64]

this is not plumming dude. it doesn't work that way. it is irrelevant where the resistor is as long as it is in the circuit. Ohms law states it clearly

[wepef3D]

@cyberlord64 Also the resitor doesn't limit the current, it drops the voltage on the LED so it doesn't burn out.

[CantCreat]

@cyberlord64

yeah only the resistivity matters

[Simtalnius]

@cyberlord64 dont hate on this guy he's awesome!

[cyberlord64]

@Simtalnius No don't get me wrong. i don't hate him. he has good videos on programming and math but maybe he should learn more about robotics and electronics before teaching others.

[Clobalize]

@cyberlord64 Yep, you are correct. Electricians doesn't need to worry about this, only if you are a phycisist.

[binboyuk]

the power starts at + and ends at - and you need to control the power before it reaches any of your componants

[ecn1984]

My replies didn't work right for a reason so I am posting this comment to say that they were to the users listed below on the same sequence:

krusherkid

SoulReaper1680

cris12esteves

[bodkin77]

did you say which size resistor to use and why? people what you need to do to calculate the resistor size to use is the use the equation R=V / I. R=resistance, V=volts and I=current. you will find a current rating from the manufacturer of the LED. let's say it's 1mA (or 0.001A). therefore R=9 / 0.001 = 9000 ohms

[MR5M]

To make it blink... see 3:57.

[Eddy34Mario]

Once I made a mistake and my circuit blew up. I was like lol.

[FutureCricketer1]

This is simple as!

[holt3138]

Neat!

[pandroidy]

this is so awesome

[SoulReaper1680]

dont the electrons/charges flow from the negative terminal to the positive terminal?

[aqren550]

because electrons are negatively charged and the energy/electricity is just the flow of electrons

[ecn1984]

There is history behind what you are saying. In the past when scientists didn't know much about atoms and they assumed electrons were positive particles. Nowadays we know that they are actually negative particles. So you will see schemes showing electrons flow from the side with the positive symbol (+) traveling to the side with the negative symbol (-). However in electronics we know that what happens is the opposite: electrons flow from - to +. It can be confusing for beginners so be careful.

[bullittkid]

like siilygul said y did the resistor get cliped at the positive?

[cris12esteves]

hello nice video .

question?. how to make it blink

[ecn1984]

There are several ways. I guess the simplest way would be using a 555 IC. You can also achieve that by using a combination of diodes and transistors.

[krusherkid]

can u use a breadboard in stead off allagator clips? if u no kinda wat i mean

[stanni1992]

Yes you can, it's good practice to use a bread board aswell.

[ecn1984]

Yes, you can use a breadboard instead - no problems with that. Aligator clips are also good for when you are soldering certain components such as transistors because high temperatures can damage them.

[jjvilm]

you're hot and smart. I'd love to know as half as much as you know. Have you graduated yet? (collage) if yes, what was your degree on?

[navjotk20]

awesome

[mentalarmory]

very cool.

[dannybetts123]

Cool video A++++++++++++++++++++

[mgmaik]

youre are the coolest in man ever!!

[kingloc4]

cool

[Metalheadplus1]

=o

sweet video =]