# Article is meaningless without diagram

Discussion in 'General Electronics Chat' started by sobellinni, Feb 12, 2016.

Feb 14, 2006
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2. ### Techno Tronix Member

Jan 10, 2015
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I agree. The article should contain the related diagram for the better understanding of the reader.

3. ### ErnieM AAC Fanatic!

Apr 24, 2011
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Presenting complete equations as the "solution" without any derivation is also not helpful.

I got as far as the first equation (just below Figure 2) which is a needlessly complicated version of a shorthand formula I use once you cancel out like terms. By this I mean there is no dependence on the output voltage suggested by this equation, as Vo is a factor in Po this term cancels out of the formula.

BTW, one may quickly derive this formula from the basic capacitor equation of I = C dV/dT, or it's non calculus approximation I = C (delta T) / (delta V). No time now but if anyone asks I can produce the derivation.

4. ### alfacliff Well-Known Member

Dec 13, 2013
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this is not a drafting site, it is an electronic circuit site., any info on componant useage should be acceptable without a drawing. filter capacitors in power supplies are extremely common, and how to decide on the correct values is of value.

5. ### wayneh Expert

Sep 9, 2010
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I wouldn't say it's meaningless - the article is a pitch for the "ripple port" design concept, and the potential of such a design to eliminate electrolytic capacitors and the aging problem they bring along. Fine. But unfortunately it offers no example of what such a design looks like and wastes a lot of brain-time on equations that aren't needed to promote the basic idea.

6. ### mcgyvr AAC Fanatic!

Oct 15, 2009
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All I see is this all over the article..
[Math Processing Error]

7. ### AnalogKid Distinguished Member

Aug 1, 2013
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I think your are confusing meaning with understanding.

ak

8. ### nsaspook AAC Fanatic!

Aug 27, 2009
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From the article:
I think others would differ from that conclusion.
https://enphase.com/sites/default/files/EnphaseElectrolyticCapacitorLife.pdf

9. ### AnalogKid Distinguished Member

Aug 1, 2013
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nsaspook likes this.
10. ### nsaspook AAC Fanatic!

Aug 27, 2009
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In this case I was researching data for a possible solar energy installation a few years ago and the question of capacitor lifetime was talked about in terms of long time liability for equipment failures so I remembered this study from then.

11. ### KL7AJ AAC Fanatic!

Nov 4, 2008
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I would say that the only possibility of having too much capacitance is that very large capacitors also have a lot of parasitic inductance, which may make the circuit counterproductive. This is all old-school stuff, though...no new knowledge here.

12. ### Wendy Moderator

Mar 24, 2008
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I had the same problem, until I hit refresh. Problem solved.

Opps, had a problem editing the wrong post. Fixed now.

Old is good, as long as it is still current. This may help me get through a stuck spot on the power supply article I'm writing for the e-book.

13. ### sobellinni Thread Starter New Member

Feb 14, 2006
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there is no Electronics without circuit diagrams. An article about a circuit with no diagram is incomplete. The forum monitor should ask Mr Williams to post relevant circuit diagrams . And as I said from what he talked about there is no such diagram, it does not exist and the original IEEE article he refers to does not refer to a simple rectifier as intimated in the first diagram, but is an INVERTER, an entirely different animal

14. ### AnalogKid Distinguished Member

Aug 1, 2013
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Not even close to correct.

The article is not about a circuit. It is about a circuit concept that applies to all switching power supply topologies (and many other circuits).

You waited 10 years to contribute something, and this is it...?

The IEEE article uses an inverter as an example for those who cannot grasp his concept without a crutch. The AAC article is not about any particular circuit. It is about a circuit concept that applies to all switching power supply topologies (and many other circuits), and is written in the style of professional engineering text books and papers.

ak

15. ### wayneh Expert

Sep 9, 2010
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I disagree only with that last bit. In attempting to dumb it down, he skips over a lot of details but chooses to leave in what I would call "gratuitous" math that nevertheless lacks the rigor of a published paper. I appreciate that it's tough to write such an article, to choose what to leave in and what to summarize or omit. A "professional" article provides references, and not just a link to an article I can't read without paying. It's not like he's the inventor, he's reporting on something created by others.

16. ### AnalogKid Distinguished Member

Aug 1, 2013
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And his images of capacitor voltage ripple are...oversimplified. I'm not saying the article is perfect, only that proclaiming it to be "meaningless" says much more about the TS than about the article.

If you divide the universe of electrical engineering writing into two groups, those with mostly pictures and those with mostly equations, then, in round numbers, text books and IEEE papers are in one group and magazine articles, particularly hobby magazines, are in the other. This is consistent with the nature of the material - concepts rely on mathematical derivation and descriptions, while applications rely on project-specific details. I am absolutely not saying that there is anything wrong with this; just the opposite, I think this is the natural order of things and I appreciate both groups for what they are.

ak

Last edited: Feb 15, 2016
17. ### tracecom AAC Fanatic!

Apr 16, 2010
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All of you do know that there is a place at the bottom of the article for comments, right?

There, you might even get a response from the author.

18. ### ErnieM AAC Fanatic!

Apr 24, 2011
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The deeper I read this article the more problems I find with it, starting from the very first sentence (which states a falsehood that the AC input power is somehow "varying") to the very first figure (which incorrectly draws the function it claims).

19. ### AnalogKid Distinguished Member

Aug 1, 2013
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Yeah, he's referring to the instantaneous value of the AC input voltage, and hence the input power.

20. ### ErnieM AAC Fanatic!

Apr 24, 2011
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Who can really tell? I've always seen power, be it AC or DC, be equal to the product of the voltage and current.

This guy has extra terms beyond that.