PCB layout of BCD clock

biggest ones easily available (easier to handle)

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

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

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.

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.

...for a start.

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

If using Google Groups

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