User talk:Rogerbrent/Archive/1

Snap DAB page

Hello Rogerbrent. Recently you recently added a new item to the Snap dab page, the Symbolic Network Analysis Package. There is currently no article with that name, and I wondered if you are planning to write one? Thanks, EdJohnston 18:16, 29 April 2007 (UTC)

Just finished writing it :) Roger 18:18, 29 April 2007 (UTC)

CircuitLogix

Hello Roger,

I noticed that you had flagged the CircuitLogix article as an advertisement. I am sorry if the article has the tone of an advertisement because the intent was to provide information about a free simulation software package that is used by electronics students around the world. Please let me know if there are any specific words or phrases that you think should be modified to make the article seem less of an advertisement.

Best regards, Carl Carl142 02:36, 9 May 2007 (UTC)

Advertisement

Hi Roger,

Thanks for the feedback regarding the CircuitLogix article. I'll give some thought to how to edit and re-organize the article so that it seems less like an advertisement.

Best regards,

Carl Carl142 14:29, 9 May 2007 (UTC)

Circuit Theorem

Hi Roger, I noticed you changed the max power theorem category for circuit theorem - but I can't find an entry for circuit theorem in wikipedia. What is a circuit theorem? Sholto Maud 10:11, 10 May 2007 (UTC)

Hi Sholto. Circuit theorems are theorems used in circuit analysis. Seems like there isn't a wikipedia entry for it, but nevertheless I believe the max power theorem, Thevenin's theorem, etc. are more accurately described as circuit theorems rather than physics theorems. Here's a more complete list of circuit theorems: http://www.bowest.com.au/library/theorems.html Roger 18:16, 10 May 2007 (UTC)

Thanks for that Roger. On the theorem talk page I've been struggling to understand the distinction between a mathematical theorem and a physics or circuit theorem. There doesn't seem to be any good criteria for determining the difference. If you have any thoughts about how to define circuit theorem in distinction to a mathematical theorem I'd like to encourage you to contribute to the discussion. Sholto Maud 01:13, 11 May 2007 (UTC)

I think the definition of a mathematical theorem ("a theorem is a statement that can be shown to be true by a mathematical proof on the basis of explicitly stated or previously agreed assumptions") works equally well for circuit and physics theorems. There could very well be a difference, but I can't think of one, sorry. Roger 02:46, 11 May 2007 (UTC)

Biasing (electronics)

Hi there!

As you pointed out, I merged the content from Bias point into Biasing (electronics). Its good to see that there are other editors looking over some of these less visited pages. Looking forward to your inputs on the same... Happy editing!

Regards, xC | ☎ 03:45, 14 May 2007 (UTC)

Hello Roger, on the same subject, it seems to me that both Voltage bias and Current bias are pretty useless as they stand, and should probably be merged into Biasing (electronics). Not sure if there's anything worth salvaging in them. Would you mind taking a look? Thanks very much, Tualha (Talk) 12:56, 9 June 2007 (UTC)

Hi Tualha. I looked at them and unfortunately they didn't really have much salvageable content, so I just redirected them to the biasing article. The solenoid example might worth mentioning somewhere else but I'll have to find a reference first. Thanks for pointing them out. Roger 19:03, 9 June 2007 (UTC)

Thank you. Tualha (Talk) 22:47, 9 June 2007 (UTC)

Hey there

Hi!

I was going through my watchlist and found this. In our textbook, it was referred to as configurational biasing. Shouldn't they be kept in then?

Also, if the content is inappropriate in that article, then where should it go?

Thanks in advance,xC | ☎ 10:49, 12 June 2007 (UTC)

Hey. I removed it because it didn't really say much about actually biasing the configurations (besides "Emitter-base jn is fwd-biased and collector-base jn is rev-biased") and I think that content is better suited to a different article. I actually moved it here, since it could be useful information. Roger 16:23, 12 June 2007 (UTC)

I think that by itself is what was expected of the page, after all a page related to biasing c(sh)ould contain configurational biasing of BJTs as well.

Anyhow, lets see how the talk page discussion there goes. If its taken in there, alls well that ends well. If not, it can be put back anytime, so no worries there.

Thanks for the quick reply,xC | ☎ 19:39, 12 June 2007 (UTC)

I'm not completely sold that configuration and biasing are necessarily closely related. The point of biasing a BJT is to establish a predetermined $V_{CE}$ and $I_{C}$. The configuration (CE/CC/CB) is determined by where you connect the inputs and outputs not by the bias. On the other hand, some configurations may work better with special biasing circuitry, but primarily configuration isn't determined by bias.

Anyway, I think the biasing article needs a major overhaul. For one thing its too BJT specific. Roger 20:22, 12 June 2007 (UTC)

What other biasing details would you like to add? There are a few ideas on the talk page of the article but I don't see much implementation of that happening. And your post to Talk:Bipolar_junction_transistor#Small_signal_amplifiers hasn't yet been replied to, after over two weeks. I think it might make more sense to put back the information into an article where it could fit, rather than leave it on a talk page where (apparently) no-one cares to have a look at it. xC | ☎ 13:42, 29 June 2007 (UTC)

The section I removed is a useful summary of the different BJT amplifier configurations, but I'm not sure exactly where to put it. Maybe somewhere in this article? Roger 17:19, 29 June 2007 (UTC)

Dunno. It might be useful there. I remember someone referring to the configs as configurational bias so I threw em in here, else I'm fine with it either way so long as the information is used somewhere. xC | ☎ 18:15, 29 June 2007 (UTC)

Hey there

I added two sections to the article Biasing (electronics) dealing with fixed bias and collector-to-base bias. Could you have a look? I'd appreciate your comments on the same. If the rough format seems alright, I'd add in more. Thought I'd ask you since you seem to be knowledgeable relating to all matters electronics.

Thanks in advance,xC | ☎ 13:37, 29 June 2007 (UTC)

Hey. Looks good, I'll try to do a few minor touch ups when I can. What reference are you using for this by the way? Since the BJT biasing section is growing and is very specific, I'm thinking its time to move it to a separate article. Roger 17:04, 29 June 2007 (UTC)

Basic electricity and semiconductor devices - Patil & Chitnis + class notes from the electronics lectures I attended in the 11th and 12th.

Well, originally it was for BJT specifically, but then a few editors said it might make more sense to have a more general article. I don't have any objection either way - if we have a specific article for BJTs, then the section which was removed (above) could be shifted in there. If not, then we could add it back to Biasing (electronics) and split off again if/as/when the page grows further.xC | ☎ 18:13, 29 June 2007 (UTC)

Kamla Millwood

I declined your speedy request on this one but put it on WP:AFD instead. Thanks for helping keep WP clean. Cheers, Carlossuarez46 19:46, 11 September 2007 (UTC)

Thank you

Appreciate your help with the Cascode article; tnx Brews ohare (talk) 23:41, 29 November 2007 (UTC)

Errors in expressions

Hi Roger: Posted comments about this on my talk page. Thanks for the interest. Brews ohare (talk) 01:38, 5 December 2007 (UTC)

Wikitables are not working

Hi Roger: All wikitables are displaying with very large spaces between entries (screen sized spaces). Have you any idea what is going on?? Brews ohare (talk) 18:39, 11 December 2007 (UTC)

Very weird. I'm seeing it on old edits that I know were okay [1]. It must be a Wikipedia bug that just popped up. If it doesn't go away we should probably report it. -Roger (talk) 19:01, 11 December 2007 (UTC)

I found that where I had used [math>\ [/math> as a spacer in tables and it worked before, I had to remove it. Even in text where several [math> [/math> are used in the same line, troubles show up. I replaced "<" with "[" to avoid compiling problems in this message. Brews ohare (talk) 21:17, 11 December 2007 (UTC)

Some problems with Common Base revision

Hi Roger:

Please look at discussion page for this article. Brews ohare (talk) 16:35, 6 January 2008 (UTC)

Inadvertent override of changes

Roger: It looks like some changes you made while I was editing common base got erased. I'm not sure how that happened, usually Wiki tells me that two editors were working at the same time. Please excuse these overrides, and take another look. Brews ohare (talk) 19:40, 7 January 2008 (UTC)

Movement of loading effects to voltage division

Hi Roger: Although a change like this could work, simple transport of the text written for common base does not work. For example, it refers to a Table that does not exist in voltage division and needs some amplifier context to make any sense. Beyond that, the loading effects for current division have to put in that article, with similar context added. Until a complete rewrite is available, my suggestion is to leave things in common base where they at least make sense and are useful. Brews ohare (talk) 10:51, 8 January 2008 (UTC)

Hi. I just noticed I forgot to remove two instances of "in the table". Besides that I think a separate article is a better place for discussing the loading effect. No point repeating it for every amplifier article. -Roger (talk) 13:10, 8 January 2008 (UTC)

Hi Roger: I like the way these articles turned out. I believe both of us deserve a bow, eh? Brews ohare (talk) 16:56, 8 January 2008 (UTC)

Amplifier articles

Hi Roger: Are you aware that there are multiple amplifier articles and they are dominated by discussion of power amplifiers to the exclusion of all else?? Brews ohare (talk) —Preceding comment was added at 19:48, 8 January 2008 (UTC)

I haven't gone through much of the amplifier articles, but I have noticed that. Much can probably be moved to the power amplifier article (currently a redirect). Do you have any suggestions? -Roger (talk) 20:09, 8 January 2008 (UTC)

Current divider

I've redirected current divider rule to current divider and made substantial changes in figures and formulas. Please take a look, Brews ohare (talk) 19:50, 19 January 2008 (UTC)

Last common gate revisions

Hi Roger: Please see talk page for common gate Brews ohare (talk) 22:16, 23 January 2008 (UTC)

Negative feedback amplifier

I've decided to avoid a detailed explanation of two-port problems and refer the reader to Jaeger. A detailed discussion puts more weight on the problem than it deserves. Brews ohare (talk) 14:40, 24 January 2008 (UTC)

Loop gain vs. return ratio

I object to this revision. Loop gain and return ratio are often confused, but we don't have to perpetuate this problem. For a simple example of where the two differ, see Spencer and Ghausi, pp722-724; Here is a quote "Is the loop gain always the negative of the return ratio? The answer is a definite no. If the amplifier has more than one feedback loop, or has bilateral blocks, which is common, the loop gain may not be the negative of the return ratio. Example, 10.7 demonstrates that loop gain and return ratio can be significantly different."

I suggest reversion to the original text. Brews ohare (talk) 18:54, 25 January 2008 (UTC)

I agree that they are different. But many authors often use them interchangeably. In the case of my edit, Rosenstark (see the "Loop-gain measurement" chapter) and Middlebrook both mean return ratio but use the term loop gain. Its unfortunately confusing, but its the reality. I added a note to clarify this in my last edit. -Roger (talk) 19:05, 25 January 2008 (UTC)

I haven't gone through the link you provided carefully, but it appears that all the examples use op amps, which I'd guess are unilateral. In any event, I see not particular merit to the methods proposed over simply using the small-signal circuit with the return ratio steps.

And, to reiterate, why follow a pattern of interchangeable usage?? It isn't followed by a number of important texts, for example, Grey and Meyer.

Brews ohare (talk) 19:12, 25 January 2008 (UTC)

The problem with finding the return ratio using the systemic (hand analysis) way in SPICE (or even in real life) is that its difficult to do so without upsetting the biasing. Furthermore, if you try replacing everything in the simulation with its small-signal equiv. (instead of letting SPICE handle that) then you have to worry about finding accurate small signal parameters (such as rbb, gm, cu, etc.) and then recalculating everything if you decide to change the bias.

I possibly should have said "return ratio" instead in my original edit, but I wanted to maintain the same terminology as my references. Middlebrook and Rosenstark are the ones responsible for most of this theory after all. -Roger (talk) 19:37, 25 January 2008 (UTC)

You make good points.

If you have derived a formula, you can put the formula in a spreadsheet where the variable gm is used in all the formulas, and then in one cell (named gm) the numerical value of gm is introduced. The comparison with the PSpice simulation is then generic - you don't need exact values to check whether the formula agrees with the circuit.

If you are after a purely numerical approach, the small-signal circuit can be made to use variables, e.g. the value of gm on the schematic is {gm} in PSpice, and its numerical value is set in a PARAM box. Any values you turn up in DC bias calculation can be stuck in the PARAM box - no need to chase them down in the schematic. A question is whether you have the right small-signal circuit, which might be something you'd like to know anyway.

I guess it's a question of expediency - where in the design process are you, and what info do you want to develop?

In any event, I found the use of the small-signal circuits in PSpice was a big help in tracking down my algebra errors.

Brews ohare (talk) 20:09, 25 January 2008 (UTC)

Your method will work, but like you said, its limited by the accuracy of your small-signal model (rather than the more complicated one SPICE uses). This method wouldn't really work for real life designs where you don't know or don't want to worry about the transistor models and just let SPICE handle. Hence the methods from Middlebrook and Rosenstark are necessary.

Incidentally, have you tried the Micro-Cap circuit simulator? I detest using PSPICE, even more so after using Micro-Cap. Its a lot more powerful in my opinion, and much easier to use; I highly recommend you try it (the student version is free). -Roger (talk) 20:35, 25 January 2008 (UTC)

CircuitLogix

Hi Roger, Thanks for the feedback regarding the CircuitLogix article. I have made further edits to make it read less like an advertisement. I hope this meets your needs. Best regards, Carl142 (talk) 13:54, 12 February 2008 (UTC)

I have done some further edits to make it less-biased (I'm a big fan of their free student version so it is hard not to be enthusiastic). But, hopefully it reads less like an advertisement now. I actually used the template for this article based on a software program called Automation Studio. Both these programs have libraries as a core component, and so I would like to keep the library section since it is a big part of the functionality. I noticed that the "Features" section was deleted already. Would you prefer to swap the features section for the library section, or can it be left "as is". Best regards,Carl142 (talk) 16:12, 12 February 2008 (UTC)

Kudos

Hi Roger: I've posted my user page at last, and made a bow in your direction Brews ohare (talk) 21:59, 20 February 2008 (UTC)

Scattering matrix

I've commented on Two-port network about scattering matrix. Brews ohare (talk) 19:49, 13 March 2008 (UTC)

Radio transmitter design

I note that you have stated that the Radio transmitter design page concentrates too much on valved circuits. I have a few things to saw to you on this matter.

1. Most high power TX systems are valved, I think that to make a 4 kW 100 MHz power amp using solid state parts would be a nightmare, but a pair of 4CX1000 tetrode valves operating in class C could be used with ease to create the final power amp. So valves are not out of date, in many ways valves are very much up to date. Also a MOSFET behaves like a triode or tetrode valve in many ways. 2. Almost all the effects and problems seen with valves can be seem in solid state systems, even transitors can require neutralization in some circuits, I know that it is rare due to the lower gain of most solid state devices. 3. There is nothing to stop you adding some solid state based circuits, I know that in theory that even things such as valved PLL could be made but I think that unless a gifted designer wants to prove a point it will never be attempted. Cadmium (talk)

Hi Cadmium.

1) I don't doubt valves are still popular for some purposes (e.g. high powered narrowband), but the Radio transmitter design article focuses almost exclusively on discrete, valve based, low frequency audio transmitters; hardly representitive of the field in general.

2) I can imagine valves being used as a final power amp, but generating AM/FM directly via valve nonlinearities is an outdated technique (and is actually more difficult to explain in an encyclopedia).

3) That could be done, but it'd be a lot of work. I propose renaming the article if you think all the valve stuff is worth keeping. -Roger (talk) 18:00, 18 May 2008 (UTC)

Nigella Lawson

I normally try to avoid stepping on people's toes at all costs if I can, yes indeed I'll explain the revert on Nigella Lawson. Firstly, you inserted a main heading entitled "Biography" with "Background" and "Personal life" as subheadings; I always think that having "Biography" as a heading is superfluous as readers know that an article about person is a biography, and in fact a biography encompasses everything in the article and not just background and personal life. Secondly the insertion of "Career" I thought made the lower-down television headings look unclear, and when you think about it "Merchandise" should probably have gone underneath "Career", so it all gets a little excessive. Finally the "Television credits" acts as a sort of filmography and I've always put that sort of thing at the bottom of articles as in the middle it looks a bit messy. You also called the article up on disorganisation; I arranged it so that the "Background" deals with her life before she was famous, and "Personal life" after/during fame which notes her marriages, children, money etc. This format acts as a progression so to speak. I hope this puts your worries to rest. Thanks. Eagle Owl (talk) 15:49, 29 May 2008 (UTC)

Thinking about something you said, I think it makes more sense to have the "Merchandise" section before "Television" as she started writing books before having her own shows. Thanks. Eagle Owl (talk) 19:54, 29 May 2008 (UTC)

South Park; removing uncited material

With regards the South Park articles I've been editing, some of those fact tags have been hanging around for months on other articles, I decided to be a bit more proactive than previous editors. Besides, the editors adding the "cultural references" can't even agree a lot of the time on what is or isn't the meaning of some of them. Southparkstudios has a faq on some episodes but the facts it gives are few and far between, simply saying "I saw in in the episode" is insufficient. Alastairward (talk) 18:07, 17 August 2008 (UTC)

Roger, there's also a somewhat lengthy discussion of it on the Super Fun Time talk page, as well as the talk page of the South Park project page. You and I are on the same side of this, I think, so if you want to stop by and comment at either of those, it would probably help. Choiniej (talk) 21:28, 20 August 2008 (UTC)

This might be of some help.Alastairward (talk) 10:34, 21 August 2008 (UTC)

Merging trivia

Hi Roger, I've been merging so-called "trivia" into the appropriate sections of a number of articles. So far I've managed to get Articles with trivia sections from May 2007 down from 265 to 148. I was wondering if you would be interested in helping? - Tbsdy lives (talk) 08:31, 27 August 2008 (UTC)

Magnum P.I.

As per your request on the talk page, I've merge in the material that has a source, and I've asked for sourced on the talk page for the rest of the material. - Tbsdy lives (talk) 11:06, 7 September 2008 (UTC)

A pleasure :-) Tbsdy lives (talk) 09:27, 8 September 2008 (UTC)

Request for opinion

Hi Roger: A page I have worked on is up for deletion as a content fork. I don't believe it is a fork, and even if it is, I don't believe deletion is the answer. Will you kindly take a look at it, and possibly render an opinion? Wikipedia:Articles for deletion/Centrifugal force (planar motion) Brews ohare (talk) 10:34, 11 October 2008 (UTC)