Does an LC Circuit Radiate Energy?

[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.

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]

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.