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How does electricity power devices?

  1. Apr 19, 2009 #1
    I've been wondering how or why electricity actually works. Resistance heaters and light bulbs just turn the kinetic energy of electrons into heat, but what about more complex devices? For example, why does a microwave oven do something useful when electrons flow in the circuitry?
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  3. Apr 19, 2009 #2


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    Accelerated charges radiate. That is the basic law in regards to a microwave. A microwave contains a magnetron. A magnetron creates a large amount of free electrons that it accelerates in a spiral fashion. These electrons then radiate microwaves that are directed into a cavity waveguide which directs them into the cooking chamber.

    A/C currents create electromagnetic radiation (akin to accelerating charges again) as well.
  4. Apr 19, 2009 #3
    Thanks for the answer, but that really wasn't my question. I was trying to find a general answer, why does any electric device work. What good are mobile electrons in devices which aren't meant for generating radiation, like computers or food mixers? Somehow the electrons manage to make things spin and I can't understand how.
  5. Apr 19, 2009 #4


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    Motors work by magnetic fields. A moving current in a wire generates a magnetic field - that attracts another magnet (or another wire) - this forces spins a shaft.
  6. Apr 19, 2009 #5
    It works because we are manipulating energy to the extent we can...though I'm not too sure if I can give you a good definition of energy.
  7. Apr 19, 2009 #6


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    I don't think there is a general answer, since different devices use different principles to convert electric current into other forms of energy. Producing microwaves is different than making an electric motor spin.

    People spend years studying a wide array of devices, in order to learn how all (or many) of them work.
  8. Apr 19, 2009 #7
    Hmm. Alright, thanks for the answers everybody.
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