I'm working on a school (early engineering) project. Our teacher told us a condition: "Do not use wall current". So I decided to use a car battery instead.
The problem: I connected the car battery to a pair of rails for testing a tungsten rod's electric properties and it sparked. Badly. I fear the same might happen to my trusty cure little 12vdc motor if I plug it trough a relay to try battery. Or to my Arduino. Or to me.
Then I remembered high school, the welding class. There I learned: The electric arc (sparks) feeds from current, not voltage. So I was wondering: how could I limit the amperage that is drawed from the battery, so my motor (or my Arduino) doesn't get roasted?
The problem: I connected the car battery to a pair of rails for testing a tungsten rod's electric properties and it sparked. Badly. I fear the same might happen to my trusty cure little 12vdc motor if I plug it trough a relay to try battery. Or to my Arduino. Or to me.
Then I remembered high school, the welding class. There I learned: The electric arc (sparks) feeds from current, not voltage. So I was wondering: how could I limit the amperage that is drawed from the battery, so my motor (or my Arduino) doesn't get roasted?