PCB layout of BCD clock

hi i build a bcd clock shown in the page

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and all the circuit works fine and now i want to build a PCB using SMD components so

1.What size of SMD component should i use?(like resistor size,capacitor size, etc....) 2.What can i do if the lines(wires) are crossed each other on my PCB?

Thank you in Advance

Yosef

Reply to
josegidayfin
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biggest ones easily available (easier to handle)

put them under the component same as you do with thru-hole only on a smaller scale.

Reply to
Jasen Betts

For capacitors you can use the smallest physical size that:

- has a high enough voltage rating

- is comfortable for you to work with

As to comfort, if you don't have a fine-tipped controlled-heat soldering iron, you probably won't see good results with anything smaller that 1206. YMMV.

For SMD resistors, keep in mind that they have very low wattage ratings (is it 1206 or 0603 that is 1/16th watt? I forget.). Except for digital pullup resistors, you still have to use the wattages specified in the schematic.

The standard method is to use a 0 ohm SMD resistor as a jumper.

HTH

Reply to
Randy Day

1206 would be best. The biggest commonly available SMD part. 0805 is next smallest and ok too for beginners to solder. Use SO package SMD parts for the IC's

Art of PCB design is choosing a layout which minimises (or even eliminates) these "crossovers". This is much harder on a single sided board, easier on a double sided board. You can use 1206 "0 ohm" SMD jumper links if you do need to "crossover" traces. You can run the traces under 1206 components and through IC legs if you need to, just like through-hole design.

Dave.

Reply to
David L. Jones

Bigger is easier to handle and takes more abuse.

Zero-ohm resistors.

It doesn't sound like you have selected any software (which makes this MUCH easier)

--nor does it appear that you have you read up on this.

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*-univers=ities-*-*-*-*-*-are-*-including-it-as-*-reference-material-*-*-*-*-*-*-*-*-=*+zzz-zz+qq+*-major-*-PCB-*-package-*-*-included-it-in-their-Help-system (25-page PDF) I'm surprised David didn't point you to this in his post.

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...for a start.

Reply to
JeffM

It would be good if you made your responses *in the group* NOT via private email.

If using Google Groups

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*.pre-dates.the.Internet+requireme=nts.for.participating+access.to.a.news.server+*.*.two.weeks.postings&strip= =3D1 instead of a proper Usenet newsreader
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*-Gravity+Free+GPL+Microsoft.Windows+501+501+*-Ag=ent+Xnews+Pan+Thunderbird+Traditional.Newsreader+501+Combination+501+501+50=

1+Cross-platform click *Reply* and NOT *Reply to author*.

In addition, if, before posting to a group, you *sign up* for that group

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and, *instead* of using an email address for a username, you would use JUST A NAME--without a domain tacked on,

*THAT* won't be obfuscated by Google and it will make it easier for others (especially other Google Groupers).
Reply to
JeffM

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