Component Footprints for FreePCB, etc

I've tried a few different freeware programs for laying out a circuit board. The problem I have is figuring out the right component name from the software's library to use for the components I have on hand.

It would be easy if the components I had came with a number or code that is used by the software. Do any supply places send such codes with their components? Or is there a logical way to look at a component and figure out which code from the software's library to use?

I'd hate to have to make my own pattern/footprint for each component I want to use simply because I have no idea what code to use in the software to match my components.

I don't know about FreePCB, as I use Eagle, but IMO there should read somewhere what package/shape/size the component has, when viewing it in the library.

The sad story is, however, that one usually has to make one's own footprints for components, when they're not available. Even more frustrating is when you find it 5 minutes after you finished creating the package.

I know the feeling...

Mankku

Hmm...I'll try Eagle...thanks!

I guess I don't get it. Eagle seems to be the same as the other two programs I've tried. Can't I just place a generic 1 meg resistor or 100nF cap without having to know the manufacturer, and code, etc? How many hobbyists keep track of or even know in the first place who made the resistor they grab from their parts box?

Well... when you make a PCB, your parts have to fit. Unless you're willing to manufacture a board then find out that your parts DO NOT FIT, then you have to tell it what size they are.

As for knowing the manufacturer, that's being a bit extreme. All you need to know is the type of footprint and the size. As for a "generic" resistor, you're probably thinking of the 1/4-watt size, which is called RC07, RCR07, or CB, depending on who you're talking to. The part number is FreePCB is RC07.

That being said, I use the RC05 size for 1/4 watters, and just bend the leads right at the exit of the resistor, but that's just a personal preference.

When you get to SMT stuff, caps and resistors get even easier, as they share size codes, and you're not likely to ever use more than 2 or 3 of them (1206 and 0805) unless you're sending boards off to be populated and assembled by machine.

Indeed... In Eagle, resistors and caps are found in the rcl package, and are grouped by the schematic symbol (EU box or ANSI zigzag). From there on, all you need to know is the type designation of the footprint and you have your generic component.

Edit: In addition, if you are unsure of which footprint to use, I guess you can place one that looks good, enter the PCB layout mode and measure the distances (pin raster, physical dimensions) and determine whether you've found the footprint you're looking for. If not, you can always remove it and try another. Maintaining a list of where to find which footprint (the ones you use the most) is useful.


ICs are a whole different story, though.


Mankku

Ok, THAT is helpful. How was a newbie supposed to figure that out LOL?

However, the footprint for a 1Meg resistor is quite a bit smaller than a 22k resistor...so how would I differentiate in the program?

Ok, disregard...I see that my resistors are different sizes because they are different wattages, not because they are different resistances. Sorry...I'm learning as I go. Makes ya cringe to know I'm working with electricity, doesn't it

Not as long as you don't mess with the mains...

Mankku

ICs still aren't *too* bad. You've got SOIC, wide soic, dip, tsop, etc. - but they're all standard, and your program *is* going to have them. At least until you get into BGA or QFNs, etc.. It's not like inductors where there is no standard, and each part has a unique footprint.

ICs still aren't *too* bad. You've got SOIC, wide soic, dip, tsop, etc. - but they're all standard, and your program *is* going to have them.

Sure, the footprints are there... But many ICs that one uses aren't defined (at least I think that's the case with Eagle)... This means that you have to define them yourself, which becomes somewhat boring in the long run... Good thing is that once you've learnt it, it isn't very time-consuming...


Mankku

This is helpful, do you know the case for ceramic capacitors?


This post has been edited by Drakkenstein on October 10, 2012 04:01 am

the original post is from 2007 .

can a mod move this and start a new topic or merge it with the other post in this section ?