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Old 3rd December 2012, 04:27 AM   #1631
gootee is offline gootee  United States
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Quote:
Originally Posted by lindjosh View Post
I've spent the better part of the day reading through this thread and I must say. Excellent looking work you have compiled Tom!
Thank you. It has been enjoyable, for me. But I am only an egg.

This planet is strange.

But almost anyone can accomplish almost anything, if they spend enough time trying. I am probably just too stupid to know when to stop, sometimes.

I guess the latest spreadsheet effort wasn't bad, for my first Excel macro, and my first VBA programming.

It turns out that you can learn how to do almost anything if you add the word "tutorial" to your google search string.

(Being a former C programmer didn't hurt. And I did a little Fortran back in the 70s, and a smidgen of Apple II Basic in the early 80s.)

I really am amazed that those tiny little differential equations and the small amount of code used to generate their numerical solution can produce such a powerful and generalized tool. You can enter "crazy" values and the solver dutifully churns out the resulting plots, some of which are pretty interesting.

Anyway, thanks again. And I'm very happy to hear that you have studied this thread. It has a lot of good stuff in it. Unfortunately, it seems to have almost died. Maybe there's no use in beating a dead horse (except, of course, for the sheer joy of it <grin>). Or maybe everyone is just busy playing with the spreadsheet. (Yeah, right.)

I did forget to mention that all of the (latest) spreadsheet's plots and calculated values that I have checked have been within a few percent (at most) of the results of my LT-Spice simulations of identical circuits (even the huge, odd-looking inrush currents). So it looks like the implemented math must be mostly correct.

Maybe sometime soon I can actually go back to working on the calculations for decoupling capacitors.

Cheers,

Tom
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Old 3rd December 2012, 04:37 AM   #1632
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Tom,
Don't think that this thread is not being read and watched. I have read all of it from the beginning to the end. Now I just have to learn how to use what you have created. Since I am utterly stupid when it comes to what you have done here that might take awhile...... But as you say if you try hard enough you can learn something new. I will have to try and figure out what goes where in your spread sheet. I originally thought that all we would end up with was a spread sheet with recommended values of power supply rating and capacitor values that we could use to fulfill or requirements for different power amp outputs and impedance loading. You did way more than that but us dummy's will have to learn how to use what you created.

Thanks for all the hard work,
Steven
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Old 3rd December 2012, 05:16 AM   #1633
fas42 is online now fas42  Australia
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Quote:
Originally Posted by gootee View Post
Anyway, thanks again. And I'm very happy to hear that you have studied this thread. It has a lot of good stuff in it. Unfortunately, it seems to have almost died. Maybe there's no use in beating a dead horse (except, of course, for the sheer joy of it <grin>). Or maybe everyone is just busy playing with the spreadsheet. (Yeah, right.)

I did forget to mention that all of the (latest) spreadsheet's plots and calculated values that I have checked have been within a few percent (at most) of the results of my LT-Spice simulations of identical circuits (even the huge, odd-looking inrush currents). So it looks like the implemented math must be mostly correct.

Maybe sometime soon I can actually go back to working on the calculations for decoupling capacitors.

Cheers,

Tom
I'll just echo other's comments, Tom, congrats on putting in the effort. I've been at other stuff, and have yet to look at the sheet, sorry!! But, I will give it a major go, shortly, I promise(!), and see if I can think of anything further to add, that may be of value ...

Frank
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Old 3rd December 2012, 02:05 PM   #1634
gootee is offline gootee  United States
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Originally Posted by Kindhornman View Post
Tom,
Don't think that this thread is not being read and watched. I have read all of it from the beginning to the end. Now I just have to learn how to use what you have created. Since I am utterly stupid when it comes to what you have done here that might take awhile...... But as you say if you try hard enough you can learn something new. I will have to try and figure out what goes where in your spread sheet. I originally thought that all we would end up with was a spread sheet with recommended values of power supply rating and capacitor values that we could use to fulfill or requirements for different power amp outputs and impedance loading. You did way more than that but us dummy's will have to learn how to use what you created.

Thanks for all the hard work,
Steven
Steven,

Thanks. It is still my intent to try to create what you mentioned. The spreadsheet I posted recently just takes what is in the system and gives how the system will perform. I still want to try to create a "backwards version", where we can give it the performance desired and it gives us the options for what to put in the system, to make it have the characteristics we would like.

Cheers,

Tom
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Old 4th December 2012, 02:17 AM   #1635
gootee is offline gootee  United States
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Originally Posted by fas42 View Post
I'll just echo other's comments, Tom, congrats on putting in the effort. I've been at other stuff, and have yet to look at the sheet, sorry!! But, I will give it a major go, shortly, I promise(!), and see if I can think of anything further to add, that may be of value ...

Frank
Thanks, Frank. I would definitely appreciate any suggestions.

I did already add a field for a user-override of the dV/dt at t=0 initial condition, since the automatic entry currently assumes that the diodes are not conducting.

I don't know how useful it might be but one other possibility that comes readily to mind is adding a delay time for the load current startup, so that the effects of the step input could be evaluated. That could be pretty-easily extended to allow a pulsed load current, with settable duty cycle. Other types of load signals might require some serious amount of work. But I guess the load current amplitude could also have a user override, if that would be useful.

If that was added, then it would also be handy to be able to specify how many cycles from the end of the simulation run the software should look at (instead of the current default of just the last cycle), when it comes up with the values it displays, i.e. the min, max, average, rms, and P-P ripple of the PSU output voltage, and the "dropout" safety margin, and the peak diode and cap currents. That way, people could manually set it to catch transients caused by the changing load current.

There are other things that could be done, to make it easier to use, like some way of automatically handling the number of steps used and the automated plot setup that would then be needed.

It would also be nice to have some easier way to zoom and unzoom the plots. Right now, you have to click on an axis label and manually set the minimum and/or maximum extent, for that axis, if you want to change it. I don't know if there's a way to make the axis-format fields obey values from elsewhere in the spreadsheet. But maybe there's a better plot object available. I'll have to check on that.

But really, if people need much more functionality, then they should be using LT-Spice, anyway.

I'll look forward to any suggestions you have. An image of the latest (unreleased) version's user interface screen is attached.

Cheers,

Tom
Attached Images
File Type: jpg v0.97scrn.jpg (387.0 KB, 99 views)

Last edited by gootee; 4th December 2012 at 02:40 AM.
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Old 4th December 2012, 10:20 AM   #1636
gootee is offline gootee  United States
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I didn't want to post new versions so often. But the new scalable plot axes in this one are very nice (or maybe I'm just amazed that I got them working). And I probably won't be adding anything else, extremely soon.

I was able to figure out how to add a "slider" control for the minimum and maximum value for each axis. So now you can zoom in on any part of a plot, very easily and quickly.

As I already mentioned, I have also added a "user override" for the initial value of the rate of change of the capacitor voltage.

I have also attached in inage of the main screen.

Enjoy.

Tom
Attached Images
File Type: jpg v0.97scalable_scrn.jpg (396.3 KB, 88 views)
Attached Files
File Type: zip Power Supply and Transformer Analysis v0.97_scalable.zip (554.5 KB, 8 views)
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Old 4th December 2012, 10:29 AM   #1637
AndrewT is offline AndrewT  Scotland
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It won't let me change mains from 60Hz to 50Hz:-
"Document opened in read only mode"

Is this a default setting on my PC, or is this a setting included in the XLS file?
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Old 5th December 2012, 01:47 AM   #1638
gootee is offline gootee  United States
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Originally Posted by AndrewT View Post
It won't let me change mains from 60Hz to 50Hz:-
"Document opened in read only mode"

Is this a default setting on my PC, or is this a setting included in the XLS file?
As far as I know, I didn't do anything that would have made the file read-only. The only "protection" I tried to use was to select "Protect Sheet", for the Transformer tab only. But anyone can Unprotect it. I did that, for that sheet only, because that sheet has a lot of things that could be changed that shouldn't be changed unless someone has new measurements to enter.

I just tried it and was able to change 60 Hz to 50 Hz and then run it. But my Excel setup is no longer the factory default.

First try going to the Review tab or menu and selecting "Unprotect Sheet".

It seems like read-only mode should only affect things if you tried to save it with the same name when it was read-only. No idea why that would afect behavior at the cell-edit level. But I don't know a lot about Excel.

You didn't say what version of Excel you have but try saving the file to a different name, and as your version of Excel's native file-type (mabe as xlsx instead of xls?). Then open that new file and see if it's better.

Another possibility is that my "Home" version of Excel is limiting my ability to share files, since it's "for non-commercial use only". I guess not too badly because Nico said he got it to work OK. But maybe he didn't try changing anything on the transformer sheet...

I selected Help and it went on line and there are quite a few complaints involving Read-Only mode. One possible solution was to install the latest Service Pack for your version of Excel. But naturally there were some who said that didn't help.

What version of Excel are you using?

[EDIT:] I have been saving the file as an Excel 97-2003 Workbook (.xls file), because I thought that would give the most widely-compatible file type. But maybe that is not the case. So I just tried saving it as an xlsx file but those can't have macros with VBA projects. So I tried the recommended xlsm "macro-enabled workbook" type and I have a bunch of cell names that conflict with built-in names in Excel (e.g. LP1, LP2, LS1, LS2, RP1, RS1, RS2, and XS2 - transformer parasitics). It automatically prepended an underscore to each of them but now I have to go track down any references in the code. After that's done, I will save it as an xlsm file and post that.

Last edited by gootee; 5th December 2012 at 02:05 AM.
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Old 5th December 2012, 02:45 AM   #1639
gootee is offline gootee  United States
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Default XLSM version attached.

The xlsm file-type version is attached, created with Excel 2007 from Office Home and Student 2007.

Same functionality as the .xls file type, v0.97, that was previously posted.

Attached screen image shows the two "axis max" sliders used to zoom in near the origin of the plot.

I made it so that the maximum and minimum axis values are printed right next to the sliders, which makes them fairly easy to use. Maybe someday I'll figure out how to do the same thing by dragging a rectangle arond the area you want to zoom to. That would be excellent. And apparently the code I already have for the sliders would work almost directly, since it uses the four "corner values". I just don't know how to get the plot coordinates for the corners of the rectangle from a mouse click-and-drag on a plot. I did see something online that looked like it told how to do that, though.

Cheers,

Tom
Attached Images
File Type: jpg v0.97scalable_scrn2.jpg (382.5 KB, 69 views)
Attached Files
File Type: zip Power Supply and Transformer Analysis v0.97_scalable_xlsm.zip (951.9 KB, 8 views)
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Old 5th December 2012, 02:41 PM   #1640
doolav is offline doolav  United Kingdom
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I think (at least in Win7) the content of MS Office docs (incl. Word), not originated from your PC, set to disabled by default. It's easy to enable it (you should see a yellow field with button 'enable' somewhere in the top of the doc).
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