Electromagnet Question?

Question

When I switch my electromagnet (just a s***w driver and a d cell battery) on it works perfectly, but when I turn it off, it retains magnetism...is this normal? If not, how can I fix it?

If it helps i'm using a rocker switch with a two pronged port for + and -

Answer 1

Yes, it's normal because when you turn a s***w driver into an electromagnet by applying a current to a wired wrapped around it. It acts like it had little magnets inside of it. So when you apply the current, these little electromagnets will allign in the same direction making the magnet stronger. The thing is that when you disconnect the current, these little magnets stay rearranged so you get a permanent magnet out of your s***w driver. It's like this experiment where you want to make a compass and you scratch the surface of a needle to magnetize it.

Hope this helps.

Answer 2

Yes, that is normal for s***w drivers made of iron or steel (an iron alloy).  Choose a different metal, you'll get a different amount of retention.

Answer 3

For most brands, yeah, that's normal. But if you want to fix it, it's really easy. Most companies don't suggest you do this, though that is because it is extremely helpful, and will make them lose money. Here's what to do..

You can either put a small houseld fridge magnet or tool magnet on the end of it, which will power down the off magnet after time, (but not when it is on, the sytem works on two different frames) so, it will lose power when it off, but not when its on. I really dont think its necessary though

Answer 4

Use a soft iron core, it has very little retention.