# Electromagnet equation help

1. Jun 16, 2006

### hover

lately i have been really interested in electromagnets. i have been building small ones and i will eventually (at least i want to anyway) build a strong electromagnet (not some toy). from what i understand you can increase the strength of an electromagnet by adding more current, turning the wire more and adding a solenoid. for a start anyway i want to know the equations on how to determine the strength of an electromagnet with an iron core. the problem is for one of course, i don't know any equations on electromagnetic strength but two, i have a really hard time with all the different fraises used in the equations (ex. permeability). I just get totally confused. can someone please help CLEARLY explain the equation for the strength of an electromagnet? any help will be appreciated.
thx

2. Jun 16, 2006

### Staff: Mentor

3. Jun 16, 2006

### hover

good amount of info but i'm still missing the equation to calculate an electromagnet's strength

4. Jun 16, 2006

### Staff: Mentor

Hmmm. You're right, no equations. I'm being lazy today, so here's a better explanation from wikipedia with equations. Hope they help. Keep in mind that the force varies a lot with the separation of the electromagnet and the target metal piece.

http://en.wikipedia.org/wiki/Electromagnet

5. Jun 16, 2006

### hover

i'm always lazy:rofl: . thx maybe i can finally figure how to calculate the strength

6. Jun 17, 2006

### Staff: Mentor

7. Jun 17, 2006

### waht

you can increase the strength of the electromagnet by making it's length short but with lots and lots of turns. That would make a shape of a disk.

8. Jun 18, 2006

### hover

i must be screwing up with the equation. somehow i get 3.17 tesla from a wire wrapped around a core 800 times with a core with 200 permeability and 1 amperes. it must be wrong. Can someone who knows what they're doing double check plz?

thx

9. Jun 19, 2006

### Staff: Mentor

It would help if you write the formula/equation, and then show the values you are using.