LC circuit and radiation

paweld

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.

AJ Bentley

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.

paweld

Thanks.

Quote by AJ Bentley

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

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).

AJ Bentley

Quote by paweld

Do you know any details about construction of such capacitors

Go take a look on the roof of any house in your neighbourhood. Almost every house has a TV aerial.

paweld

Interesting :)

K^2

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.

Antiphon

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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paweld	LC circuit and radiation Tweet 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.

AJ Bentley	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.

K^2 Recognitions: Science Advisor	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.

Antiphon	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.