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Chris333
Joined: 25 Sep 2008 Posts: 74
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Posted: Fri Dec 05, 2008 8:27 pm Post subject: |
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The 1.73VDC goes down to 1.72-1.71VDC when the trim is turned down. |
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pray59
Joined: 05 Sep 2008 Posts: 88 Location: Fremont, CA
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Posted: Sat Dec 06, 2008 12:22 am Post subject: |
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Well, that controller beats me too! I don't understand why it won't work like the one Armand built. _________________ -Robert Ray |
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Jax
Joined: 04 Dec 2008 Posts: 44 Location: London, UK
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Posted: Sat Dec 06, 2008 8:48 am Post subject: |
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Perhaps he didn't quite give you the correct schematic.
And don't ask me, I'm an old fashioned gal and didn't do anything like electronics at grammar (cookery, needlework, yes). Don't understand it at all. |
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kingbf
Joined: 26 Dec 2008 Posts: 1
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Posted: Sat Dec 27, 2008 3:42 am Post subject: PWM throttle |
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Thought this schematic for a PWM motor control might prove interesting. Haven't built or tested it, but it looks promising.
kingbf
www.uoguelph.ca/~antoon/circ/circuits.htm
go to - Pulse Width modulator, CD4093 |
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Chris333
Joined: 25 Sep 2008 Posts: 74
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Posted: Sat Dec 27, 2008 5:48 am Post subject: |
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I'll wait for someone else to test this one first. |
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rmyers
Joined: 19 Nov 2008 Posts: 73 Location: Evanston, IL USA
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Posted: Sun Dec 28, 2008 6:16 pm Post subject: |
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I was browsing for a suitable pulse width circuit and came across this simple one: http://www.eleinmec.com/article.asp?28.
British source so part numbers for British supplier, but simple enough to translate for other countries. 3-15 v. input so we should be able to do 4.5 or 5 v. for T. 3 a. maximum current so no problem there.
Uses a pair of 555s to get the wave form and a TIP131C as the power transistor.
Where the motor is shown on the schematic, remove the motor and put in a dpdt for direction control and the track power outputs.
Bob |
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AndyA
Joined: 21 Oct 2008 Posts: 33 Location: Southampton, UK
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Posted: Mon Dec 29, 2008 8:08 am Post subject: |
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I'm having a couple of problems with that link. First, although I can see the "shopping list", there's an error message at the top saying that the article text is missing. Second I can't see the circuit diagram, although a fairly familiar looking schematic popped up in a little box when I moused over th 555 timer in the list.
Any ideas?
regards
Andy A |
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rmyers
Joined: 19 Nov 2008 Posts: 73 Location: Evanston, IL USA
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Posted: Mon Dec 29, 2008 3:51 pm Post subject: |
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AndyA wrote: | I'm having a couple of problems with that link. First, although Any ideas? |
Sorry, works for me - Firefox 3.0.1, MacOS 10.4.11 and SeaMonkey 1.1.13 on OLPC XO build 767 (Fedora 9 based).
What's your browser?
Try this to find it - Google 'pulse width modulation meccano' it should be the first hit.
Bob |
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AndyA
Joined: 21 Oct 2008 Posts: 33 Location: Southampton, UK
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Posted: Mon Dec 29, 2008 4:17 pm Post subject: |
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Okay, I'm also using the latest Firefox, but it turns out that's not the problem. Your Google search terms turn up the thing no problem, article and all including schematic.
Clicking on your link gives the shopping list but no supporting text. I'm guessing that it's the trailing '.', but I would have expected a wrong link to just give a 404. I guess one part of their database is stripping the '.' from the article parameter, the other not. C'est la vie.
thanks for your help. The circuit looks good and should truly work at dead stop even with the low voltage output, but I have no trains to check whether it will creep. However, the same problem will occur as with an earlier one posted here - if it works first time out, great, if not, it'll most likely take a 'scope to trace the fault, unless it's just a joint and can be found by inspection.
I'm going to have a look at
EDIT: looks as if the upload was truncated.
I'm going to look at their other suggested solution of using a computer (USB) output. This would have the advantage that if the software works on one USB machine running a given OS, it "should" work on all.
But to get back to the original topic, nice find in that circuit.
regards
Andy A |
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rmyers
Joined: 19 Nov 2008 Posts: 73 Location: Evanston, IL USA
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Posted: Tue Dec 30, 2008 3:56 am Post subject: |
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The link should be: http://www.eleinmec.com/article.asp?28
I was trying to be grammatical and ended the sentence with a full stop -- which the link creator thinks to be part of the link.
Sorry, Bob |
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