Glowing pencil lead

[Adamskys]

TOUCH IT!

[melonman425]

The multimeter is like a timer lol!

[OldSkull87]

@Univac93 & BarneySaysHi: or maybe he just have 1mOhm resistor in series?

[mr1880]

mine blew up

[trivuong]

first day learning from my electric class i light up a Resister.

[virusz1000]

the new neons for my Mustang RC

[tskune139]

@virusz1000 LOL

[hellomang100]

you made a toaster wire!

[aei05h1]

@GTAEFLCMissions You got problems lol.

[Univac93]

I wonder how the Multimeter can show the current if it's set on miliVolts??? (Btw. I've got nearly the same one) :D

[BarneySaysHi]

@Univac93 Maybe he uses a current transformer

[boraboy4ever]

now crush up the semiconductive graphite and dip a piece of steel wire in it and place in a vacumn and you have something called... a light bulb.

[FMxClan]

its not lead is graphite :L

[toadsEATbugs]

wats da current

[natertater323]

hardest thing in the worl to melt. out furnaces at work which run at 4 megawatts 4500 amps of current at 13kv have a crucuble graphite bottom. they withstand great temperatures for a little while before they eventually burn up. they usually last around 4 months then we have to change out the furnace and put a new one in. but hell with a 10,000 degree elcius arc runnin nonestop i dont see how in the fuk this shit stand that for even any length of time

[lorenzol1996]

This brings a whole new twist to the "pretending to stab yourself with a pencil" joke!

[SamuraiClinton]

Just imagine sticking graphite into a USB port!

[19KamiKaze42]

"The instrument on the left shows current in Amperes" as u have described

And its setted on mV (millivolts)

what the F!!

First learn how to use a multimeter

[cyborg4r]

@19KamiKaze42 electrical technician here, he could be measuring the voltage trough a shunt resistor, silly. Measuring the voltage drop of a 1 miliohm resistor in milivolts gives you the current in Amperes (from ohm's law I = V/R).

[molo265]

@cyborg4r true.

[xato909]

my exploded º-º!!

[CASSANDRA3866]

What equipment is used here? please tell?

[bestamerica]

'

how about a 9 volts

[MissTahr]

using 9V battery and 0.9mm pencil lead... nothing happens!

[SonySasuke]

Wow, somebody's eventually gonna take this idea and make a USB barbeque.

[Speculantscooter]

I applied an 18V AC current at 0.8A. Shit got crazy.

[midgetking101]

if u paint the lead with a sharpie it will smoke w.e color u pained it with...

[hitachi088]

@midgetking101

No...

[midgetking101]

@hitachi088 well i colored mine pink and the smoke was pink.

[Ifeanichukwu]

BOOM

[XxXDeathIsArtXxX]

do you realize your dvom says mV (millivolts) not Amperes? so your just showing how much fractional voltage you pu through, its not 6v its like .06 or such

[TheRimeOfIcarus]

Although he isn't measuring current, it still makes sense:

Small voltage and a really small resistance yields a large current, hense why the graphite is very hot.

[67tr876]

could this work better if you put it in to a vacumm and then put a gas in the bulb ?

[hitachi088]

@67tr876

yeah , it will last more longer i think .

[superbungabunga]

so how long can that glow for, whats the life

[Comikkaze]

my friend stuck a piece in an electrical socket and it popped

[halo2party]

Tell him he fails for me.

[ThePositronicMan]

@Comikkaze No one should attempt to imitate this. It popped because of the sheer current through it, which could easily do similar things to your body.

[madbasementlab]

@Comikkaze i did that too

[ZenoTH74]

Imagine you writing with that ;)

[torianaownsu]

more like, melting pencil lead

[StingrayNate]

I tried this with no success... I tried using 5 volts all the way up to 9 volts and got nothing... any advice?

[zernestro]

@StingrayNate weird...i used 12ac...light a lot. at 30Vac it eyeburns quite some.

If it didn't do much, your source can't put out as much current as the load, which is the lead,:) demands.

I think you may have done it with an adaptor that has less than 500mA current to offer, but you need much more. It tried 9V with 800mA and could barely get a 1cm long o,6mm piece smoking a little. you need more powa

[dumle29]

@StingrayNate do you have enought amps on your power supply?

[RideTTD2003]

looks like the multimeter on the left is actually set at voltage (according to the top of the display reading "mV")

[zernestro]

yp...what do you get if you measure a voltage across a 1Ω resistor?:)

[RideTTD2003]

nothing, if there is no voltage running through the resistor. if you measure the resistance of a 1 ohm resistor, you would get 1 ohm.

[zernestro]

but if there is voltage across the resistor, you are reading current through it in volts;)

[RideTTD2003]

dude, you measure voltage in volts, and current in amps. a meter doesn't read current in volts, it isn't possible - i went to electrical school for this stuff

[zernestro]

looks like school tamed your ability to think out of the box.

i'll give you an example.

you have an 1Ω resistor, and put 2 Volts across.

you take a voltmeter, and lets presume it has infinite internal resistance. You measure voltage across the resistor to be 2 volts. Because the resistor is 1Ω, the current through the resistor is 2 Amperes. R=U/I=1, meaning how many volts your voltmeter reads, that's the number of amperes flowing through.

[zernestro]

so If avian6's voltmeter show 5mV, and he says (look at the info) it is reading current in Amperes, it could be because he's measuring voltage across a 1miliΩ resistor, which is in series with the pencil lead.

right?

[JohnnyX50]

@RideTTD2003 agreed, it does look as though the meter is set to mV (millivolts) not Amps =/ I also passed a 2 year city and guilds in electronics so agree with you entirely =]

[jheetman]

nice, i see how the ampere flow dropped as the element heated, this handy little tidbit made me understand a tiny bit more about electricity.

[salemcripple]

Here's good site if you want to learn more. w w w.allaboutcircuits (dot) com /vol_1/chpt_2/1. html

[CassetteMaster]

Will the lead still write after it's burned out?

[icedrinker8]

it went out because it burned out.

[windoes98se]

if you use 9 volts at 800ma with .5mm lead it wil get hot enough to melt crayons but not prodice light

[DellMan94]

how much amperage did you put through it

[salemcripple]

The volt/ohm meter is reading amperage.

[triangletrexx]

is this a hairglide of your sister fixing the mine?

[alburtisfirefighter]

can you relight it after you shut it off? eh nvm ill go try it lol

[4BUR4M3]

it fades like a dimentional portal *-*

[isgoodno]

lol, yea, it does.

Scotty, four to beam up.

[frank30700]

caca boudin

[wolfdude117]

its the current (amps) that makes it glow brighter

[nanolith777]

primitive incandescent lamp :P

[koenie12345]

yours glows, mine started smoking

[markii63]

i think it is just some residue on the graphite stick.

[jomomwashere]

Maybe not enough volts.

[Minifig666]

@koenie12345 His glows, yours started smoking, and in my science lesson on a 5A 12V PSU mine exploded!

[midgetking101]

@koenie12345 it only smokes for a little bit ... and then it starts glowing

[dumle29]

@koenie12345 too thick a lead

[MissTahr]

@koenie12345 Mine did nothing! 

[rollercoastermaniac2]

@koenie12345 u need 6 volt bat.

[OldSkull87]

@koenie12345: try to apply higher voltage. Mine needed 24-28V for 2-2.5A

[edulitto1]

@koenie12345 need more power.

[blueroKaru]

what's the temperature of the graphite when glowing?

[Dafroft]

nice

[MileyCyrus700]

i want to write with it!!

[gfyhdhbyhgj]

And after, me!

[MileyCyrus700]

haha that wouldbe so funny

[merdamo]

its a light saber

[markii63]

Millivolt, actually SCNR

[Watcher3223]

Yeah, I misspelled.

Though, I just read the description, and the multimeter was supposed to be reading current in amps with the volts at a constant 5V in DC.

[DiachiLaser]

the last time I tried this the lead just exploded, though, maybe 32V@2A was a little too much ? :P

[jomomwashere]

Clearly.

I say 9v is the max.

[DiachiLaser]

It's not really the voltage that matters though, it could be really high current.

[cuki555]

tomaz, very good

[alexander0025]

i wonder how it would write

[naruto12299]

wouldn't the graphite snap or break graphite isn't very resistant

[cenzo188]

So, is the voltage decreased over time, or does the resistance of the graphite decrease, shorting out the power?

[allumina]

I would imagine the voltage was "decreasing over time" because so much of the initial power was being lost through heat.

[toontownmaster222]

how to do that send a message back plz!!!!

[LizzyAston]

Shouldnt the voltage rise when it is heated? Increased resistance...?

[i8246i]

you've got it backwards

resistance impedes current

[LizzyAston]

yer i know, therefore voltage must be increased in order to maintain the current

[fazzolettopirata]

i try with 0.7mm graphite and 12 volt battery

after one scond the graphit is explosed

why???

why don't glow???

[aaronz101]

To high a voltage, try a 1.5v battery at first, see what happens. Then, if necessary, you can keep adding 1.5v batteries in series until you get the desired effect.

[jenni560]

I would guess you are just useing too high a voltage.

[markii63]

It should glow, this is not a side effect.

[orangie84]

Did you reduce the power or did it as they say burn out..

I mean how long will it stay lit.. (glow)

How safe is that?

Does it get hot?

I mean could this be used as a light?

Or is it too dangerous

[avian6]

The voltage on the lead was constant 5V. You can see from the video that it burned out in less than a minute.

Yes, incandescent things are usually hot.

[lapulapu12345]

@orangie84 HOT AS MUCH AS ABOVE 100'C

[godof2moons]

@orangie84 it blows u if u set it on fire

[fiskrens6]

@orangie84 fucking retard

[photosmarty4]

cool a homemade light saber!

[maclover201]

The current is dropping because as the temperature climbs, so does electrical resistance.

[cortexedge]

As the temp climbs the resistance drops ;)

[maclover201]

Isn't it the opposite?

[cortexedge]

nope

[maclover201]

Ya sure? Why do certain metals superconduct when they get really cold?

[cortexedge]

Oh...sorry...sorry :D

I messed them up:D

Sorry again :)

[maclover201]

That's OK.

[joeylawn36111]

Exactly. Resistance drops,therefore increasing current, which further reduces resistance. This is called Thermal Runaway - it's why the lead burns out....

[avian6]

Check the video again. The current is constantly falling, so given the constant supply voltage the resistance is rising, not falling. That's not so much because of the temperature (the lead heats up really quickly, so you don't notice it), but because it's getting thinner due to ablation.

Thermal runaway is something that happens in semiconductors, where you can in fact get the property that effective resistance falls with temperature. It's not possible with ordinary conductors like graphite.

[joeylawn36111]

my bad...

[UnrealKillaz]

@avian6 iv tried this a couple times it got so hot it melted the metal on my alligator clips

[strikeme5]

how do u get -00.0 lol

[RicoElectrico]

-0 means the value is negative but it was to small and rounded to zero...

[DrazaKhan]

Sweet! A mini light saber!

[strikeme5]

yeah it BURNS to i tred it man it scars

[Amishman35]

POP! goes the pencil lead.

[avian6]

I recorded this with Canon Ixus 55

[EatOoze]

The Ixus ROCKS!

[Danny7930]

cool and what type of camera do u have? its perfect for youtube