I'm just starting up with electronics and looking to control an electromagnet with the Arduino. I'm wondering what hardware setup will make the most sense to use to turn the electromagnet on and off at around 10 times per second. I plan to make the magnets using coiled wire. From what I have read, I need to get a transistor to switch power on and off. 

In summary:

* Should I use a transistor? If so, what transistor works well with Arduino for this application?
* How do I supply power to the electromagnet? A schematic or explanation would be super helpful.

Thanks in advance!