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LC circuit and radiation

  1. Jul 21, 2010 #1
    I wonder if LC curcit radiates energy? Probalby not because according
    to equations energy is not lost during its vibration. But I heard it was used
    in very simpe radio receivers. Is it true.
  2. jcsd
  3. Jul 21, 2010 #2
    An LC circuit is the basis of most radio transmitters and receivers. Simple and otherwise.

    Essentially, the aerial of a radio is the capacitor in an LC circuit specially designed so that it loses energy producing radio waves.

    In the usual physics and electronics studies of reactive and resonant circuits, the parts are assumed to be designed to avoid losses.
  4. Jul 21, 2010 #3

    Do you know any details about construction of such capacitors (probably they generate
    electric field outside the area between plates and this induce magnetic field and so on).
  5. Jul 21, 2010 #4
    Go take a look on the roof of any house in your neighbourhood. Almost every house has a TV aerial. :smile:
  6. Jul 21, 2010 #5
    Interesting :)
  7. Jul 21, 2010 #6


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    Keep in mind, also, that any real circuit will have resistance as well. You can usually account for losses to radiation by factoring them into effective resistance.
  8. Jul 25, 2010 #7
    Also, the difference between LC circuits on paper and in real life is that the paper circuit is assumed to be of zero physical size so that capacitors have no inductance and inductors have no capacitance. Real LC circuits will always radiate even without antennas.
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