Re: gEDA-user: Footprints for bridge rectifiers ?

[armdeveloper <armdeveloper@xxxxxxxxx>]

On Mon, 2007-07-23 at 17:08 -0400, DJ Delorie wrote:
> > I'm looking for a footprint for a 20A bridge rectifier.
> > 
> > http://www.diodes.com/datasheets/ds21220.pdf
> 
> Just draw it in pcb.  Set up a metric grid, 0.1mm, draw the four vias
> (in order! 1,2,3,4), draw lines on silk.  Select all, convert to
> element, save element to file.
> 
> Sometimes I edit the footprint file to fix pin numbers.
> 
> Via drills should be 5 mils bigger than sqrt(x*x+y*y) of the leads (I=1.10mm
> R=0.8mm, so sqrt(I*I+R*R) = 1.36mm or 53.5 mil, so drill = 58 mil.
> 
> Via copper is usually 1/3 the distance between drills.  E=7.5 mm avg,
> minus 1.5mm for the drill, is 6mm left.  Make the copper 2mm annulus,
> or 2+1.5+2 = 5.5mm diameter.

Thank you very much for explaining that in detail.  Exactly what I
needed.




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