User talk:RogerAF

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Revision as of 10:17, 21 December 2007 by RogerAF (talk | contribs)
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Aloha from Honolulu, I have several areas of interest. I've been servicing recording studios here in honolulu, since the late '80s. Also concert sound, video projection, and theatrical lighting systems. I play electric rock-blues guitar and know what guitar players want from their Marshall amps. And I do recording engineering and production, so I know what recording engineers need from their monitor amps and speakers.

I have several projects I'm currently working on. And several ideas I want to develop ito new projects. I was thinking about some of those when I came across this site. It seems so serendipitous, I just had to join and write something.

I've spent the last week or so working on PC board layouts of several voltage regulator designs I've built and used over the years. I built a replacement for a recording console power supply regulator, that has been working now for near 10 years. I couldn't find the high current regulators that the original design used, so I used a pair of 723 ICs and external pass transistors and made my own substitute. The 723 has been bery bery goot to me! I used another pair of them to make a bench supply that adjusts from 12V to 35V plus and minus are individually adjustable and the pass devices have a 20A rating. I use this to experiment with various discrete op amp designs. A modern version of the Jensen 990 is my goal.

I've also recently built my first switchmode regulator based on TIs TL494 PWM controller IC. My experience with switching regulators is limited. I never had to repair one, only replace the complete unit, so I'm having to learn about them on my own. I've collected a lot of documentation and learned about buck, boost, buck-boost, fly-back etc. But it is all "book learning" as opposed to "hands on" at this point.

I thought these regulators might interest someone. I will post the schematics and artwork here eventually, but I need to find out more about how that is done. If anyone is interested, let me know.

Aloha, RAF


Aloha, RogerAF. Welcome to Open Circuits.

I hope you enjoy reading OpenCircuits and sharing your knowledge with us.

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Thank you for sharing your experiences here. I also have a bunch of "book learning" about switching regulators.

Have you seen National's "simple switcher"? The web application is nice for taking specifications like "up to 3 A output current", input voltage, and output voltage, and rapidly converting it to a circuit that National guarantees will work -- rather than fiddling around with prototypes for a few days.

Have you seen The 3-transistor Black regulator? Or the +5v to +13v Converter also by Roman Black? It makes me wonder why I used to think switchmode regulators required a complicated IC to control them.

Should we start a page on switching regulators here at Open Circuits?

--DavidCary 00:35, 18 May 2007 (PDT)

Hi David, In response to your question re a switching regulators page. I'd vote yea and expect that a linear page should be its partner. Given that the two types are so different in approach and conception. Linear regulators are very easy for me to understand, because of my years with audio equipment--most of which used linear supplies. Switching supplies are found in audio processing units, but the repair was generally to swap in a new card rather than trouble shoot for bad components.

I haven't done anything with switching regulators other than building my first with a TI TL494 PWM controller IC. I looked at Roman Black's designs (Thanks for that turn on) what elegant simplicity! I'm in awe. I am happy to contribute to a linear regulators page--I have several discrete opamp based designs for dual tracking supplies etc. I'd like to see more switching designs, to expand my own knowledge and raise my conciousness. I've peeked at National's online design software, but never took the time to try anything.

I have a little project that requires +3V, +5V, and +&- 15V. I'm trying out TI's 2W DC/DC converters: DCP020515, DCP020503, and TPS5430 Step Down Converter for that application, but it's on a back burner for a while. If anyone has any experience with these I'd like to hear about it.

I've just been going through the documents I've downloaded and the samples I have on hand from Texas Instruments. The more I think about it, the more a page for switching regulators makes sense. I think it should be broken into different manufacturers offerings with a cross reference at the beginning or the end--assuming there is crossing. There may be more differences than duplications--I don't know, so that is something to be researched. This should be presented to the whole community for feedback.

RAF 00:28, 23 May 2007 (PDT)

I responded to your question on User talk:DavidCary. I responded there, rather than here, because the last time I put half of a conversation in one place, and the other half in another place, I only confused myself :-). --DavidCary 10:22, 23 May 2007 (PDT)

editing line drawings

For editing general line drawings, the best editor I've found is "inkscape". Download it for free ( ).

Some people use inkscape even for sketching schematics. Other people prefer a specialized schematic editor.

Congratulations, you've already posted more images to Open Circuits than I have :-).

--DavidCary 12:51, 23 May 2007 (PDT)

switching power supply design

"SMPS switching power supply design: circuits, schematics, PCBs, electrical engineering reference, software, and other free online resources" edited by Lazar Rozenblat.

writing on wiki

Some of my favorite pages about writing on wiki are:

I'm dropping little snippets of information here, even though I plan to separate them out into another page someday. The "sentence to page" and the "big buckets first" essays should explain why I do this, rather than creating a fresh page now and placing 2 snippets of information into it.

-- 20:54, 11 June 2007 (PDT)

Anonymous Edits

To who ever edited this page earlier. You did no favors to anyone here. You did not contribute anything. You removed information that others spent time and thought composing and sharing with the community. If you did this by accident, you owe it to yourself and everyone else (not only on this wiki, but on every wiki) to learn how to use the tools properly, so you don't damage things.

If you did this knowing what you do, then you are a malicious prankster and should be banned from the site.

I prefer to give you the benefit of the doubt, so in the future, be more careful.

RAF 06:09, 9 July 2007 (PDT)

More: Anonymous Edits

Someone seems to have nothing better to do than F with stuff they shouldn't. This is the second time in as many weeks that someone stuffed a whole bunch of links at the top of this page and deleted most of the text towards the bottom. This is very poor behavior and being it's the second time, it feels malicious, no benefit of the doubt about it.

--RAF 10:15, 21 December 2007 (PST)