Talk:RL circuit

message: What if the input signal is not a pure sinusoid?  Why is the article restricting the frequency domain analysis only to pure imagnary frequencies?  There is a much more general form involving Laplace transforms where, instead of using
:  Z_L \ = \  j \omega L 
the complex impedance is
:  Z_L  \ = \  Ls  
where s is a complex number
:  s \ = \ \sigma + j \omega 
Sinusoidal steady state is then a special case where
:  \sigma \ = \ 0  
and 
: s \ = \  j \omega 
This approach then enables you to use some interesting and powerful techniques:
* Solution of the differential equations using polynomial functions of s
* Laplace transfomations of inputs and outputs to derive complex valued functions in terms of s
* Analysis using complex valued transfer functions, also in terms of s, that are simple ratios of the complex valued input and output functions
* Identification of poles and zeros of the transfer functions, and plotting the poles and zeros in the complex s-plane
* Calculation of gain as the magnitude of the transfer function and phase angle as the argument of the transfer function.
* Frequency domain analysis involving not only pure sinusoids but also damped sinusoids
* Fourier decomposition and analysis of arbitrary (non-sinusoidal) signal inputs and outputs.
:-- Rdrosson 12:45, 4 November 2005 (UTC)
replies: text: If you look slightly further down the page, you'll see that Laplace domain stuff is included there. -Splashtalk 12:52, 4 November 2005 (UTC)

text: Yes, I see what you are saying.  But actually, the article barely scratches the surface of these ideas, and everything prior to the mention of Laplace Transforms can be vastly simplified by a much more general and elegant set of techniques.  If you read the the list of bullet points I created (above), I don't see any of these concepts other than one brief mention of Laplace Transforms in the article.  Furthermore, even the discussion of Laplace misses the key point:  you don't need to restrict the input signals to sinusoids -- you can represent and analyze the behavior for virtually any input signal .   -- Rdrosson 20:09, 4 November 2005 (UTC)
replies: text: The entire section 'Complex impedance' has no reference to RL circuits.  Yes, it's probably needed to understand the frequency domain methods used in the rest of the article, but if each of the hundreds of articles that use these methods, RC circuit, LC circuit, RLC circuit, amplifier, Colpitts oscillator, etc. has an introductory section on complex impedance and eigenvalues, we'll get tremendous article bloat.  This section should be removed and replaced with a warning that readers will have to know complex impedance and Laplace transform to understand what follows. --ChetvornoTALK 13:02, 9 October 2008 (UTC)
replies: text: Well, as it happens, I created Template:Complex Z, call as , for just such occassions in the articles I write.  I also think that introducing the s-domain in this article is of limited use to the readers, many of whom are not familiar with the method.  Yes, it is a more powerful concept, but in something this simple jω-domain or direct solution of the diff equations will do for most cases.  Save it for articles that can really make use of itElliptical filter for instance. SpinningSpark 17:20, 9 October 2008 (UTC)
thread_title:  Complex Impedance Methods 

message: I was looking down the RL and RC articles, and I noticed they are not in the same layout.
I believe since there are many similarities between RL and RC circuits it would be beneficial to someone reading the two if the layouts were the same.
The one that stood out the most to me was the Natural Response. On the RC page it is at the top and called 'natural response.' On the RL page it is farther down
and called 'zero input response' and has an aka. 'natural response'  —Preceding unsigned comment added by 209.142.189.102 (talk) 19:39, 3 February 2011 (UTC)
thread_title:  RL RC similiarites 

message: Sorry about the SVG conversion missing the italics. I didn't notice that in preview. The SVG is actually correct, with italics, but the thumbnail is being generated incorrectly. I will pursue the correction of the thumbnail generation before applying the SVG change again.  — Preceding unsigned comment added by 24.19.214.109 (talk) 17:35, 23 October 2011 (UTC)
thread_title:  SVG Conversion 

message: The energy delivered to the resistor during any interval of time after the switch has been opened for a circuit.
:\omega = \frac{1}{2} L I_0^{2} (1-e^{-2 \frac{R}{L} t})
While t ≥ 0.
This is very unclear for a number of reasons.  The title says power but the expression is in units of energy.  It is not explained what switch is opening.  The meaning of I0 is not given.  I am also not convinced it is correct.  If we assume the switch in question is intitially shorting the circuit and when opened connects a supply and I0 is the final current in the circuit.  The boundary condition at t=∞ will have a steady power of V2/R dissipated in the resistor.  The energy expression should therefore have a term in t as the energy will be steadily increasing.  The boundary power will not depend on L as is implied by the given expression.  I also make it that there is a another exponential term in the energy equation.
This needs more context on what the source is discussing.  It would also benefit from not using omega as a symbol for energy (I think the source was probably using w).  It is probably also more appropriate for the time domain considerations section. SpinningSpark 22:11, 5 November 2013 (UTC)
replies: text: Fixed the problem. I improperly created the header.—CKY2250 ταικ 00:33, 6 November 2013 (UTC)
thread_title:  Delivered power