https://answers.yahoo.com/question/index?qid=20110402003424AASoRYe
https://www.sparkfun.com/quiz/46
https://answers.yahoo.com/question/index?qid=20110402003424AASoRYe
https://www.sparkfun.com/quiz/46
https://learn.sparkfun.com/tutorials/voltage-current-resistance-and-ohms-law