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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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30th Jul 2019, 7:17 pm | #1 |
Nonode
Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,587
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Drawing circular log scales?
I need to make a circular log scale to replace the missing one on a signal generator but I can’t find any way of generating a software based version.
Is there something I’ve missed? Can anyone help?
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Richard Index: recursive loop: see recursive loop |
30th Jul 2019, 10:56 pm | #2 |
Heptode
Join Date: Dec 2014
Location: Lincoln, Lincolnshire, UK.
Posts: 583
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Re: Drawing circular log scales?
I am not aware of software, but have not needed or looked. It is something which may be not too difficult to do by hand. You only really need the length of circle perimeter (or length of the scale if not full circle) then calculate a normal straight log scale to fit that length. Then transfer over. I can see it would be tedious but with the right tools, practical.
Hopefully someone will have done this and know the tricks (or better still - software). One other option would be if someone were able to take an accurate photograph of such a scale from identical model. |
31st Jul 2019, 5:09 am | #3 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,321
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Re: Drawing circular log scales?
Something like this?
Done with Abacom's Front Designer, all customisable. Change text, rotation, line lengths etc within the program. |
31st Jul 2019, 8:19 am | #4 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,050
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Re: Drawing circular log scales?
Hmmm... Can't have '0' on a log scale!
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31st Jul 2019, 9:48 am | #5 |
Nonode
Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,587
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Re: Drawing circular log scales?
That's right. The one I have is a photocopy of an original, it reads from 10 to 100 over an arc of 290° on a diameter of 4.25" (108mm).
I want to produce a drawing so that I can send it off to have one made in etched aluminium.
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Richard Index: recursive loop: see recursive loop |
31st Jul 2019, 11:44 am | #6 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,321
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Re: Drawing circular log scales?
Removed the 0 and changed it to 290deg scale.
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31st Jul 2019, 12:02 pm | #7 |
Nonode
Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,587
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Re: Drawing circular log scales?
Thank you! Please could you change it so the marks are on the inside of the arc and reverse it so that 10 is where 100 is? That would be an excellent solution!!
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Richard Index: recursive loop: see recursive loop |
31st Jul 2019, 12:12 pm | #8 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,050
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Re: Drawing circular log scales?
I've just crudely put a ruler on my monitor face and measure chord lengths: 10-20; 12-24; 20-40; 30-60; 40-80; 50-100 all measure 72mm. so the angles are the same, exactly what would be the case for a log scale!
I like it |
31st Jul 2019, 1:20 pm | #9 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,515
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Re: Drawing circular log scales?
In principle, that's correct. A real life pot will jump to zero at the end of the track, though.....
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1st Aug 2019, 4:17 am | #10 | |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,321
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Re: Drawing circular log scales?
Quote:
Do you want the arc to remain where it is and the division marks come in from there Or Move the arc to the outside of the division marks as they currently are? And do you want the lines slightly thicker? |
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1st Aug 2019, 6:02 am | #11 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,321
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Re: Drawing circular log scales?
So much for the household chores, started raining and of course it was outside chores.
Attached as first pass depending on which way round you want the changes. Also attached as a pdf as that is nicer than the jpg's. |
1st Aug 2019, 3:01 pm | #12 |
Nonode
Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,587
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Re: Drawing circular log scales?
Hi Terry, thank you, it's looking almost right!
I attach a photo of the dial I'm trying to duplicate, I don't know why I didn't do this before....
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Richard Index: recursive loop: see recursive loop |
1st Aug 2019, 3:44 pm | #13 |
Hexode
Join Date: May 2005
Location: Wigan, Greater Manchester, UK.
Posts: 479
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Re: Drawing circular log scales?
You might want to have a play with meterscales, I can't offer any help with the program.
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1st Aug 2019, 5:46 pm | #14 |
Nonode
Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,587
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Re: Drawing circular log scales?
Thank you, unfortunately I don't have a Windows computer....
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Richard Index: recursive loop: see recursive loop |
2nd Aug 2019, 1:41 am | #15 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,321
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Re: Drawing circular log scales?
Picture was a good idea.
I'll have a play a little later and see how close I can get it. Are you able to measure the distance between the end of the division mark and the number and the lengths of the marks? |
2nd Aug 2019, 3:00 am | #16 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,763
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Re: Drawing circular log scales?
There are ways round operating system issues.
This Mac has Oracle Virtual Box installed. This creates a number of virtual machines and I can load any operating system I want on each machine. so I got a legit copy of XP. I can open a window on the Mac OSX screen with XP running in that window, and run windows software on it. David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
2nd Aug 2019, 11:13 am | #17 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,321
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Re: Drawing circular log scales?
This is about as close as i can get it from the picture.
Let me know if it needs any tweaks. |
2nd Aug 2019, 11:37 am | #18 |
Nonode
Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,587
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Re: Drawing circular log scales?
Hi Terry, that is fabulous! Thank you, I'll be able to finish rebuilding the signal generator...
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Richard Index: recursive loop: see recursive loop |
2nd Aug 2019, 11:39 am | #19 | |
Nonode
Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,587
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Re: Drawing circular log scales?
Quote:
I have run Virtual Box on the Mac but I don't have a currently licensed version of any Windows system.
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Richard Index: recursive loop: see recursive loop |
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2nd Aug 2019, 3:02 pm | #20 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
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Re: Drawing circular log scales?
If you know how to write PostScript, it would take about a screenful of code to produce a scale like that!
If you are running any Unix-like system (i.e., Mac or Linux) then you probably already have GhostScript installed, which is a suite of programs for working with PostScript files including displaying them and converting them to other formats.
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