When Is Carbon an Electrical Conductor?

I use my VC9804A+ to test my "中华绘图铅笔 2B" pencil.
The resistance is 11.4 Ω.According to vedio,the voltage is 13V.
Then the power=U^2/R=13^2/11.4= 14.8w.
This power is just like a little lamp in my room!

The fact it glows and flows electricity doesn't mean it is a "good" conductor. In fact it is the opposite a strong resistor in this case. If it resists electricity the flow goes in a different direction and that is in the form of heat/light. It just simply "can" conduct electricity but I don't see it as a "good" conductor.

looks like a lightsaber :-P

i agree with conquerall, it does kinda look like a light saber. And acts like one to. :D

smurrah.....either you have never studied anything that has to do with electricity, or you sat and giggled at the wall during basic DC theory in class. If you dont know what your talking about please refrain from arguing with a magizine that is pretty much dedicated to knowing about simple things as this.....

think about it like this:

if resistance caused so much heat, your house would go up in flames everytime you turned something on. Since you are posting ridiculous comments on here, I am going to guess your house is still intact....

smurrah.....either you have never studied anything that has to do with electricity, or you sat and giggled at the wall during basic DC theory in class. If you dont know what your talking about please refrain from arguing with a magizine that is pretty much dedicated to knowing about simple things as this.....

think about it like this:

if resistance caused so much heat, your house would go up in flames everytime you turned something on. Since you are posting ridiculous comments on here, I am going to guess your house is still intact....

What do you think an incandescent light bulb is? A resistor. Would you put your hand on a light bulb? Resistors give of heat. The fact that this resistor made of carbon from pencil graphite burns through paper like a torch means it isn't flowing the electricity from one end to the other without resistance. A conductor means, it can flow electrons. When something doesn't flow electrons from one end to the other. I was simply putting it in layman's terms that YES: it *can* conduct electrons but NO it is not a *GOOD* conductor of electrons.

that was awesome

i'm going with donkey buff that was awesome, you guys are looking way too into it if i wanted a crash course in electrical DC theory then i would have taken a crash course in electrical DC theory. not read the posts to a magazines blog.

To smurrah.

High resistance doesnt mean lightsabers. If thats the case then il just replace my light bulb with wood(which has a high resistance). You are right about resistance giving heat, but there are 2 reasons why a wire gives up heat 1. Resistance 2. Current, as we know conductors like wires have different sizes because they have different uses and different current usage. A thin wire for example is used to flow small current to devices like phones and a thick wire flow large current like in a powerplant. If you flow a large current in a small wire, what will happen? I think you know already, thats the reason why light bulb filaments are super thin.

To dimensio

Resistance has little to do with the lightsabers. The lead burns due to overflowing of current in the lead. If you apply a lesser voltage on the lead, i think it wont burn.

(TO PHD'S; CORRECT ME IF IM WRONG)

I've seen this trick published as a crude, but workable flashlight if your car breaks down at night. the graphite in a pencil lead connected to your car battery burns pretty bright.

http://beecherbowers.com

light bulb:100ohm
pencil:10ohm
130v (~125) divided by 100ohm=1.3A
13v divided by 10ohm=1.3A
So the current is the same.
I think that the more current is the more heat.
Or why would a shorted battery get hot?

Also light bulbs are fairly good conductors.
1. They are made of metal
2.I can't think of any common resistors that are less than 100 ohms [however there are very useful 220 ohm resistors].