I have the electromagnetic fear...

A double-pole double-throw relay or switch can reverse the the terminals of a motor, electromagnet or battery.

Click to expand...

Thanks! So... relays are really electrical switches. And now, how does it works with a transistor? Do you know a good schematic for that kind of application? My electromagnets are supposed to be 24V/150R = 0.16A but I will use only 12V I think.

A transistor can turn a relay on and off.
Transistors and Mosfets can make an H-Bridge which is a double-pole double throw electronic circuit.

Google has links to switches and relays. Here is DPDT contacts wired for polarity reversal:

So tonight I built this **broken link removed** Everything works like a charm except my electromagnets. **broken link removed**

Those magnet are suppose to be very heavy no? Actually, they are weak. They should be as strong as neodymium magnets no? For testing all the thing, I used only 12V instead of 24V. Do you think it's just because of the 12V?

I would ask my question in another way...

Should I continue with the MSA-R and use 24V, will the electromagnets be stronger that way?

Or...

Should I focus more on doing a circuit Relays and transistors? Would I get more power?

I'm almost there...
Thanks for answering me for my last question about electromagnets!