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BananaPlug
Joined: Jul 04, 2007 Posts: 307 Location: Philly
Audio files: 5
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Posted: Wed Dec 26, 2007 8:27 pm Post subject:
Need advice on PCB layout for Alpha pots |
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Hi,
I'm working on a PCB layout in ExpressPCB and need to make a "custom component" for the 16mm Alpha pots with the DPDT switch. You can see them here:
http://www.smallbearelec.com/Categories.bok?category=Potentiometers+and+Trimpots
Also known as Mouser 313-1600F-Value (catalog page 577).
I've got it for the most part but I'm not convinced I have the right sizes for pad and hole (says he squinting at a ruler held against the pin). I guessed .046 for the holes.
Are any of you working with these? |
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DrJustice
Joined: Sep 13, 2004 Posts: 2114 Location: Morokulien
Audio files: 4
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Posted: Thu Dec 27, 2007 3:38 pm Post subject:
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Hi BananaPlug!
Normally I'd grab a datasheet, but as I'm sure you've found out there doesn't seem to be any easily available for this part. The best things you can do is to measure - a caliper is highly recommend for this. Make your hole diameter the largest measure across the pin (if the pins are square/flat), then add some for the through plating. Your PCB manufacturer will have the thickness of the through plating as part of the PCB specs. If in doubt, use at least an additional 0.1mm for the hole diameter.
It is also often good to oversize the holes a tiny little bit, say 0.1mm, especially for footprints with many strangely spaced pins. It is no fun to get your board back in an unstuffable condition...
DJ
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toppobrillo
Joined: Dec 10, 2005 Posts: 766 Location: oakland, ca
G2 patch files: 1
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Posted: Fri Feb 01, 2008 2:38 am Post subject:
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maybe this will help:
http://www.taiwanalpha.com.tw/chinese/p_e_49.htm
i didn't find the exact part you're asking about here, but the pinsize looks the same to me. i did a couple boards with pads for 16mm pots like these- the pins say they're 1mm wide, so i made the hole diameter about 1.27mm- but these aren't plated-through either. i believe the pad diameter i have is about 1/8"..
josh |
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BananaPlug
Joined: Jul 04, 2007 Posts: 307 Location: Philly
Audio files: 5
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Posted: Fri Feb 01, 2008 8:47 am Post subject:
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That's very helpful. The ones I'm working with are at the top of http://www.taiwanalpha.com.tw/pic/p_e_52.jpg. You can buy them at Small Bear Electronics.
I'm going to be making some boards to hold three of these with all connections (and a few spare pads) brought to a 34pin header. They pots will be very closely spaced to allow a vertical row of six (2 boards) to fit on a Frac Rack panel. Use skinny knobs.
http://squiggletronics.com/files/pcbs/pswx3prelim.png
(preliminary - file won't be there forever)
If anyone wants any speak up. |
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