1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How does electromagnet works?

  1. Jul 20, 2008 #1
    does it have an ac or dc current?

    I think I still don't understand what is the difference between ac and dc.
    they both currents, both changing electric fields. (not static field since they are moving)
    they both creates a magnetic field.

    then what is the difference?
    (DC = steady magnetic field AC = changing magnetic field) ?

    to create a magnetic field, can the particles just move (steady) or they should accelerate?

  2. jcsd
  3. Jul 20, 2008 #2
    Actaully, dc will work also, but under conditions.

    When a dc source to an electromagnetic is turned on(or turned off) there is that period of time that the electromagnet expresses an electromagnetic field as the current intially rises(or falls). When the dc sorce is steady, no such effect occurs.

    In other words, a "pulsed dc" source can work for an electromagnetic, as well as "sawtooth" or any other form of none steady dc. And though the classic "sine-wave" is normally associated with ac, it is very easy to create a dc sine-wave... which will drive an electromagnet.

    Just some thoughts...
  4. Jul 20, 2008 #3
    All that is needed for a magnetic field is a moving charge; if by charges accelerating you're referring to changing current, then the magnetic field also changes.

    You essentially need a changing current (the result should be a changing magnetic field) whether it be AC or DC (AC is convenient because its always changing) for induced voltage.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook