Talk:Direct current

message: I do not agree with the section claiming DC sometimes refers to "constant polarity." DC is really the constant component of a voltage or current signal. The rectified signal has a DC component, but it also has many frequencies added to the signal. I think the point that is desired to be made is the conversion of AC to DC through a rectifier. However, a full-wave rectified signal is not DC. Mak17f 05:11, 10 December 2005 (UTC)
replies: text: Please see the second to last paragraph of this article.  The bigger problem here is that the term 'DC' has been overloaded.  For example, DC orginated as an abreviation for direct current - a current that does not periodically reverse direction. Thus, a phrase like 'DC voltage' becomes 'direct current voltage' which doesn't make much sense at all. Further, a 'DC current' becomes 'direct current current' which is redundant. We EEs commonly refer to the DC component of a signal thereby equating the term 'DC' to the time average of a time varying signal or, if we are in the frequency domain, the 0 Hz component of the signal. Additionally, we talk of DC voltage or current sources when we mean constant voltage or current sources. Finally, we refer to DC circuits when we mean a circuit without memory (the voltages and currents in the circuit do not depend on past or future values of voltages and currents). There are probably other examples where the term 'DC' has become shorthand for something other than a uni-directional current. Alfred Centauri 15:14, 10 December 2005 (UTC)
replies: text: Perhaps my concern is more that I think the most common use for the “DC” terminology is being a synonym for “constant;” be it constant voltage or current. Because of this, I feel the last couple paragraphs that you mention should be placed in the more prominent position in the beginning of the article. If in some circles DC is a synonym for constant polarity, it should be as an aside rather than the main definition. I agree that it seems the DC term is thrown around in many situations. Possibly in this article the different definitions should be clearly presented? I’ve rearranged the article such that uses and definitions are separated. Maybe this way the debate can be focused in these areas.Mak17f 18:50, 10 December 2005 (UTC)
thread_title:  Does DC mean one-way or constant? 

message: I want to know what are the limitations for the length of the cable to be used for Positive connection for a DC Welding machine. Let me explain more we want to do welding for one equipment which is at a distance of 15metres from the welding machine we can get the power supply for the welding machine there only. For this i want to know is it safe to keep welding machine at 15metres distance and do the welding. In this case what is the earthing procedure we need to follow is it necessary to earth nearer to the equipment or we can earth the common earth of the machine which is nearer to the welding  machine. Please suggest me what to do —The preceding unsigned comment was added by 202.124.177.50 (talk) 11:02, 5 December 2006 (UTC)
thread_title:  Length of the cable to be used for Arc welding machine 

message: CC constant.
DC sign constant.
--Nicoguaro (talk) 14:08, 18 March 2008 (UTC)
replies: text: Within the world of EE, DC is a synonym for constant, e.g., DC (non-timevarying) circuit analysis, DC (non-time varying) source, DC (non-time varying) component etc.  Alfred Centauri (talk) 01:27, 19 March 2008 (UTC)
thread_title: DC is not the same that CC

message: It would be helpful if someone who knows about such things could amend this article to discuss how it is that much if not most of the world relies on direct current. If the disadvantages of direct current are so great, why does all of Europe have DC systems?  —Preceding unsigned comment added by Ahistorian (talk • contribs) 02:36, 26 August 2008 (UTC)
thread_title:  Use of direct current 

message: I added the WikiProject Electronics template since this article pertains to this WikiProject; the WikiProject Energy template was already added, but none of the parameters were filled. I referred to the templates in the talk page of the article for AC current.
WikiProject Electronics Class and WikiProject Energy Class: I rated the article as being Start-Class because it has one reference; from http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Electronics/Assessment and http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Energy/Assessment, under the description for Start-Class articles, the rating of Start-Class should be applied for "An article that is developing, but which is quite incomplete and, most notably, lacks adequate reliable sources". If an article has only one listed source, it is, at best, start-class, regardless how informative, well-written, or long it is. This is simply because such articles need to be more verifiable, which Wikipedia holds in very high regard. The editors did do a good job, especially in formatting and organization; the article only needs more information and references for verification.
WikiProject Electronics Importance: Direct current (D.C. [or just DC]) circuits are absolutely fundamental to electronics, since every standard electronics class begins with the properties and equations that apply to a DC circuit. An understanding of DC circuits is the first step towards an understanding of higher-level concepts in electronics. Since knowledge of electronics requires knowledge of DC circuits, I rated this article as being of top importance.
WikiProject Energy Importance: Direct circuits form a paradigm of electric information and energy transfer. Indeed, networks of energy transfer can often be simplified (conceptually) into a DC circuit with components for those who do not know much about physics or when details are neglected. However, unlike in electronics, general knowledge of the dynamics of energy transfer in physics does not require knowledge of DC circuits. For these reasons, I rated this article as being of high-importance.
This article is technically lacking an infobox, so I noted that.
--Some Old Man (talk) 01:23, 22 May 2009 (UTC)
thread_title:  Description of the filled parameters in the WikiProject Electronics template and the WikiProject Energy template. 

message: DC circuit contains very little not already desecribed here, and this unreferenced stub definition could usefully be merged here to give it context. --Wtshymanski (talk) 20:52, 17 April 2012 (UTC)
replies: text: What, exactly, would you discuss only at "Direct current" that is not appropriate for "DC circuit" or the reverse?  These aren't even two successive chapters in the physics textbook. --Wtshymanski (talk) 21:56, 17 September 2012 (UTC)
replies: text: Which argument are you using?  You have one for and one against there. 86.130.168.254 (talk) 11:44, 18 September 2012 (UTC)
thread_title: Suggest merge

message: The graphic for the article that shows "pulsing" is incorrect. The correct term is ripple.Nanoatzin (talk) 08:55, 11 September 2012 (UTC)
replies: text: Also (less commonly) known as 'pulsating DC' (even though the term is technically inaccurate).  The standard symbol used actaully shows pulsating DC rather than DC with ripple. 86.130.168.254 (talk) 11:47, 18 September 2012 (UTC)
thread_title: Graphic

message: Current is defined as the flow of charge, in articles that deal the concept of current specifically, using the expression current flow when talking about charge flow creates an implicit definition which is never defined.  --Kyohyi (talk) 16:59, 11 October 2013 (UTC)
replies: text: At the moment the lede uses a definition for Direct Current as the unidirectional flow of charge.  In the third sentence of the lede says "Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams.".  "current may flow" implies a flow of flow of charge.  I would like to change this sentence so that we don't imply a flow of a flow of charge.  --Kyohyi (talk) 20:52, 15 October 2013 (UTC)
replies: text:  Please, learn a level of English grammar, syntax and sentence parsing appropriate to the level of pedantry that you're pushing. "Current flow" is a commonplace idiomatic expression that is very widely used in an unambiguous sense. Yet in deference to you and your claims of tautology, we are not strongly resisting your goal to rework uses of it. However "current may flow" is simply a different construct; there is no tautology here, even to your nitpicking level. There is no error here and we should not "fix" it merely to make an article inaccessible to normal readers. Andy Dingley (talk) 22:13, 15 October 2013 (UTC)
thread_title:  Current Flow 

message: Usually when people learn about electricity, DC will come first before AC. And it seems like such a perfect world when using DC, as everything can be calculated so easily without frequencies. Hence I want to include a section of the pros and cons of DC to let readers have a sense of real world electricity.  — Preceding unsigned comment added by 204.98.7.11 (talk) 06:32, 7 December 2016 (UTC)
thread_title:  Direct Current Vs Alternating Current 

message: The content added here by User:Dhanushbbb and removed here by User:DocFergus comes directly from this macao.communications.museum page.  Agree it's likely a copyright violation. Dicklyon (talk) 17:31, 1 October 2018 (UTC)
thread_title:  Copyvio 

message: Perhaps some will like my bold addition to the lead and some won't. 
In modern semiconductor electronics, the distinction between DC and AC is somewhat fatuous. For purposes of circuit analysis, even though the power supply is entirely DC, taking advantage of the superposition theorem (more than one independent source equals the algebraic sum of the responses caused by each independent source acting alone) it's commonplace to model mean current flow as a DC component, and the variable flow as a superimposed AC component, amenable for analysis of spectral content in the frequency domain. For example, digital circuits with a pure DC power source are vulnerable to crosstalk which is effectively an AC behaviour, generated by the spectral content of the sharp digital switching edges. 
My own perspective is that there are two mental models of good pedagogy: one assumes that this is the first article a person reads, on a slow and steady progression into more advanced treatments (beaten into our heads in K12 and beyond); the other perspective is that for the average somewhat harried person, this might well be the last encounter with the subject en route to a hasty interim conclusion. For the second class of people (in the world as opposed to in education), it's an extreme disservice to impart a quick impression that DC and AC are easily and consistently two divided worlds apart. That's my own 2 cents anyway. YMMV. — MaxEnt 18:56, 6 August 2021 (UTC)
replies: text: The lead of the article should be a concise overview of the contents of the article. --Wtshymanski (talk) 21:52, 10 August 2021 (UTC)
replies: text: There *is* a definition in the "Various definitions" section. It is the only one *with* a citation.  None of the graphics match it.  It gets worse when you go to Pulsed DC, where there is one citation from one sixty-year-old textbook. DC is a waveform with a frequency of zero.  And, oh yes, the value of Vrms does work out, but you have to do the whole Taylor series, which I won't type here.  We have a duty to be right, here in Wikipedia, because it's being quoted all over the internet.  Please don't tell me that the unfiltered output of a full-wave rectifier is DC, 'cause it aint. Even by the simplest test: you can feed that waveform into the primary side of a transformer and get something out on the secondary.  Sure, you can have DC with a ripple and it's still DC, but you can't tell me V=|sin(omega)| is DC. Rhadow (talk) 00:29, 14 January 2022 (UTC)
thread_title:  Fatuosity