Talk:LC circuit
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I'd like to add this material but it may be too technical for the article.
- A capacitor stores energy in an electric field (depending on the voltage across it), an inductor stores energy in a magnetic field (depending on the current through it). If we start with a charged capacitor and connect an inductor across it, current will start to flow out of the capacitor (reducing the voltage across it) through the inductor, building up an magnetic field around the inductor. Eventually the capacitor will have no energy in it, but the inductor will be storing energy in its magnetic field. With no voltage across it the current will slow, and energy will be extracted from the magnetic field to keep the current flowing. Energy will therefore be extracted from the magnetic field, producing a current which will charge the capacitor with a voltage of opposite polarity to what it possessed originally. When the magnetic field is completely dissipated all the energy will again be stored in the capacitor (with the opposite polarity) and the process will repeat in reverse.
I wanted to avoid that E=.5*C*V^2 and E=.5*L*I^2 so said 'depending on' but that might be sacrificing accuracy for simplicty, and not that simple. other problems. Can anyone clean it up to usable form? RJFJR 07:10, Mar 26, 2005 (UTC)
- Looks fine to me. Just put it in and it will be tweaked as part of the article. — Omegatron 14:58, August 22, 2005 (UTC)
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- I'd say that information is the opposite of technical, compared to the information that is already there. I can understand it, though I'd quibble with "all the energy". It needs some phrasing tweaks in the bit "and energy will be extracted from the magnetic field to keep the current flowing. Energy will therefore be extracted from the magnetic field, producing a current". I notice the information is not now present (1 year 1 month later). Too bad, this is the sort of description Wikipedia needs.
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[edit] Series and Parallel circuits
The present page only covers a parallel tuned cicuit and is therfore not complete. It should also include a series tuned circuit as these also come under the title "LC circuit(s)". Light current 04:45, 2 August 2005 (UTC)
Indeed, the article should also contain information about series LC circuits. In its current condition it's quite different from the articles for RC_circuit and RL_circuit. Pink-isnt-well 17:04, 23 September 2006 (UTC)
[edit] Basic info
One thing this article doesn't say is... what does "LC" stand for? GAH! --tgeller 17:11, 9 August 2006 (UTC)
- L and C are the common symbols for inductance (inductors) and capacitance (capacitors), respectively. ~MDD4696 16:44, 14 August 2006 (UTC)
[edit] Almost information free
I'm sure that everything in this article is meaningful and informative to students of Electrical Engineering, but it is lacking a great deal in terms of communication to the young inquiring mind or to the general public. Consider the first diagram,
. It shows a loop with a only an inductor and a capacitor. The article claims it resonates. No antenna, no voltage source, no power source, no current source: it seems unlikely. Perhaps with superconductors?
It seems to me that the entire present article should be pushed down a ways into some sort of "technical depictions" area, and a more open discussion of the topic should precede it. Supposing I had a capacitor and an inductor and a battery (and I do have all these things) what I want to learn is: how can I hook them up to form an LC, and how will it behave? I can look up what an inductor or a capacitor is and does, but I have no real sense of what it means to say that the current alternates between them. From the diagram or with them in series, I'd think it was impossible for there to be more current in one than the other (unless the frequency is incredible).
As an example, suppose we draw a circuit with a voltage differential applied across the I&C in parallel. A simple text description of the result would be tremendously illuminating: the circuit will resonate at a frequency defined by (equation), where by "resonate" we mean that current from the voltage source will vary as (picture of waveforms). As voltage is increased,...,as current increases,.... I don't know what a "current source" means in practical terms absent voltage. I suppose a battery is a current source to a short circuit and a voltage source to an open circuit? I don't think any general discussion should make use of the truly ideal concepts without any concrete representation (if that's what a current source is). Does the circuit even do anything when constant voltage is applied?
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- wikifiyied oscillator for you. I am planning to draw some images about how to add damping, driving, leaking.Arnero 11:53, 18 November 2006 (UTC)
[edit] History
Invented by William Thomson, 1st Baron Kelvin ? Arnero 16:47, 18 November 2006 (UTC)
[edit] Impedance of Series/Parallel LC circuits
It states under the the Series LC circuit section that it "act[s] as a band-stop filter having infinite impedance at the resonant frequency of the LC circuit."
I am no expert but when plug the numbers into the equation I get 0 impedance at the resonant frequency, making it a band-pass filter.
The opposite is true for the Parellel LC circuit description as well. It states that "the parallel connected circuit will act as band-pass filter having zero impedance at the resonant frequency of the LC circuit." Plugging the numbers in again, at the resonant frequency the impedance is infinite making this a band-stop filter. —The preceding unsigned comment was added by Charlesthomasbarnes (talk • contribs) 17:48, 17 January 2007 (UTC).
[edit] Resonant Frequency - Algorithm Correction
The Algorithm presented for finding the Resonant Frequency declares that ƒ is equal to an irrational expression: 
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Using the method of Rationalizing the Denominator, the Algorithm should be rewritten as: 
This is not a serious issue; however, to some it appears very improper. —Preceding unsigned comment added by 75.89.6.226 (talk) 01:29, 14 April 2008 (UTC)
