Re: gEDA-user: Footprint recognition

[Goran Mekić <meka@xxxxxxxxxxxx>]

> On 16/12/09 09:57, Goran Mekić wrote:
>>     Is there a way to recognize what footprint I need for an element
>> other
>> then printing them all and comparing it to real element? Let's say
>> it's 2200uF polar cap. I know it's RCY*, but how to figure out what's
>> *? Thanx!
>>
>>
>
> You'll remember the most common parts' footprint names eventually. For
> capacitors, I'd recommend using the RADIAL_CAN set of footprints. They
> are macro-based footprints, with their single argument being the
> capacitor's diameter in mil (1/1000th of an inch). For example, a
> capacitor that's 200mil in diameter (~5mm) would use the footprint
> "RADIAL_CAN 200". Currently, the RADIAL_CAN macro supports diameters of
> 200, 300, 400, 500 and 600 mil. This way you can simply use a vernier
> calliper to measure your real-life capacitor's diameter and pick the
> closest value for the footprint. No need to waste ink.
>
> Of course, an alternative method would be to find a way to print out the
> whole footprint library at once on a single sheet (with the footprint
> names included!); if you keep that sheet safe and clean, you can simply
> use it for reference without having to print stuff out more than once.
>
> Note that useful macro-footprints exist for other parts than capacitors
> as well; you can use AXIAL_LAY (300|400|500|600|800) for resistors and
> axial capacitors or inductors, and DIODE_LAY (300|400|500|600|800) for
> diodes (but keep in mind that DIODE_LAY has pin 1 as the cathode and pin
> 2 as anode).
>
> IC footprints, of course, are obvious (DIPn/SDIPn/SSOPn/TSSOPn... with
> 'n' being the number of pins). Transistors, not so much. There appears
> to be no proper standard for the pin layout of most transistors; e.g. a
> TO92 package can be C-B-E, C-E-B, B-C-E, B-E-C, E-B-C or E-C-B for
> bipolar transistors. The footprint, in this case, can simply be "TO92",
> but you have to make sure the pins are properly matched between gschem
> and PCB.
>
> As for more exotic parts, you're SOL. Often, you'll end up designing the
> footprint yourself since there are no satisfactory predesigned ones.
> This list can help you with that most of the time, though.
>
> -Peter
>
>
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>
    OK, another problem with footprint. I can list files that belong to
PCB package and filter out footprints, but I have no idea what to do
with macroes. For example, I've stumbled upon bridge rectifier
(http://www.gotwind.org/diy/images/Bridge_Rectifier.jpg or
http://media.digikey.com/photos/Vishay%20Genreral%20Semi%20Photos/W005G.jpg),
and because there's no element in pcb that looks like rectifier, I
suppose there is a macro for this (just guessing). Is there a way to
list macro footprints? Thanx!

-- 
FreeB(eer)S(ex)D(rugs) are the real daemons



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