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I have made an attempt to make an electromagnet.
I got a 10 inch iron rod with insulated copper wire wrapped around (see image)
I didnt have enough wire for the whole rod, so the wire is in two seperate sections

I tried a AA 1.5v battery, two AA 1.5v, a 9v, two 9v and a big 6v plugged in both ways (negative, positive).
None seem to work.

I thought it may be the two sections connected together, so i tried all the above batteries again on only one section, and it still didnt work.

Can anyone help me out here ?

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11 Replies

woken (author)2009-06-03

try it without insulation

Plasmana (author)2009-05-21

Are you sure it is an iron rod? It looks more like an aerial rod to me... Try using a steel nail instead.

NachoMahma (author)2009-05-15

. If you have a VOM (multimeter), check the battery voltage when the coil is connected. I'm guessing it drops to close to zero.
. Measure the resistance of your coil and divide that into the voltage of your battery. That will tell you how much current the battery will need to supply. I=V/R.If that's 16 AWG wire, it has ~5 ohms per thousand feet, so you don't have much resistance there.
. Follow GH/Gjdj3's suggestion. Using this chart and Ohm's Law, you can compute how much wire you need to use to match your battery's output.

lemonie (author)2009-05-16

What about the inductance / impedance of the coil? L

NachoMahma (author)2009-05-16

. It's a DC circuit.

lemonie (author)2009-05-17

It still has an effect, you'd say "insignificant"? L

oxidase (author)2009-05-16

i'l try what you said NachoMan, luckely, i learned all those formulas and stuff in school :D

lemonie (author)2009-05-16

Wire looks too thick. If you used something thinner with more turns you might have more luck. L

Gjdj3 (author)2009-05-15

Here's my suggestion...

Use very thin, uninsulated, magnetic wire. Also, use a lot of battery power. Maybe even a car battery.

See this episode of burn notice. The magnet he made wouldn't be strong enough to actually wipe the disks, but it's on the right track.

Goodhart (author)2009-05-15

I personally believe it is the thickness of the insulation of the wire causing you the problem. The further removed from the core the wire is, the more power you'd need to overcome that distance. If you have access to "magnet wire (sometimes called transformer wire, as they use it in transformers too), that is wire that has only a chemical coating over it, you will then be placing the magnetic field closer to that rod, AND you will be able to wrap many more turns from one end of the rod to the other.