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Homework Help: Electronics converting sine waves to current

  1. Mar 29, 2008 #1
    How are sine waves converted to current??
    Im doing avionics in physics at the moment and we are talking about receivers... i now that the resonate oscilates at certain frequency and the antenna picks up the sine waves that are at the frequency... but how are they then turned into current??
    thanks!! :)
     
  2. jcsd
  3. Mar 29, 2008 #2

    dst

    User Avatar

    They get cosined :rolleyes:


    No really, "sine waves" are a mathematical tool, not real waves! What you're thinking about are photons/electromagnetic waves.

    It's an outcome of Maxwell's equations, if I remember correctly. An alternating current in an antenna causes electrons to move back and forth. According to Maxwell, if a moving charge decreases in velocity then it has to emit energy (in the form of photons). These photons carry a specific amount of energy and the reciever picks specifically these up.

    If I remember correctly, the reciever also picks up all sorts of crap which is where a ****load of techniques (both mathematical and physical) to isolate the one signal.

    Another "if I remember correctly", the antenna has to be a certain length or some other to induce a standing wave in the antenna.
     
    Last edited: Mar 29, 2008
  4. Mar 29, 2008 #3
    It's done with a type of recifier (in receivers is called the detector)
     
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