Does an LC Circuit Radiate Energy?

Click For Summary

Discussion Overview

The discussion centers around whether an LC circuit radiates energy, exploring the theoretical and practical aspects of LC circuits in the context of radio transmission and reception. Participants examine the implications of energy loss, the role of components like capacitors and inductors, and the differences between idealized models and real-world applications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that an LC circuit likely does not radiate energy because energy is not lost during its vibration, although they acknowledge its use in simple radio receivers.
  • Another participant asserts that LC circuits are fundamental to radio transmitters and receivers, indicating that the aerial acts as a capacitor designed to lose energy and produce radio waves.
  • A follow-up post requests details about the construction of capacitors in LC circuits, speculating on the generation of electric and magnetic fields.
  • Another participant emphasizes that real circuits include resistance, which can be accounted for when considering energy losses due to radiation.
  • One participant points out that real LC circuits will always radiate energy, contrasting this with idealized circuits that assume zero physical size for components.

Areas of Agreement / Disagreement

Participants express differing views on whether LC circuits radiate energy, with some suggesting that they do not under ideal conditions, while others argue that real-world circuits inevitably radiate energy. The discussion remains unresolved regarding the extent and conditions under which energy is radiated.

Contextual Notes

Participants note limitations in the assumptions made about idealized circuits versus real-world applications, including the presence of resistance and the physical characteristics of components.

paweld
Messages
253
Reaction score
0
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.
 
Science news on Phys.org
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.
 
Thanks.

AJ Bentley said:
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).
 
paweld said:
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. :smile:
 
Interesting :)
 
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.
 
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.
 

Similar threads

High School Why do capacitors not discharge everything immediately in LC circuits?
  • · Replies 15 ·
Replies
15
Views
2K
Determining Inductance L in an LC Circuit
  • · Replies 5 ·
Replies
5
Views
2K
High School A question about induced current in LC circuits
  • · Replies 4 ·
Replies
4
Views
2K
EM Waves Generated by an LC Circuit?
  • · Replies 30 ·
2
Replies
30
Views
5K
High-energy LC oscillatory discharge: what kind of switch?
  • · Replies 19 ·
Replies
19
Views
2K
What explains the current flow in a LC circuit?
  • · Replies 4 ·
Replies
4
Views
3K
High School Why does my LC circuit not oscillate its energy between Electric & Magnetic fields?
  • · Replies 152 ·
6
Replies
152
Views
8K
Find the charge q(t) for an LC circuit
  • · Replies 2 ·
Replies
2
Views
3K
High School "Prove" that LPG burns with a blue flame ....
  • · Replies 15 ·
Replies
15
Views
2K
Undergrad How does radiation become heat?
  • · Replies 20 ·
Replies
20
Views
12K