Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: "alan00463" <alan00463@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, December 30, 2005 3:50 PM
Subject: [Homebrew_PCBs] What pad size?


>I am about to layout my first homemade PCB,
> using Eagle 4.16 Light. My circuit will
> include:
>
> small transistors - 2N3904 and 2N3906
> quarter-watt resistors
> half watt resistors
> small diodes
> large diode
> small LEDs
> N.O. pushbutton switches
>
> What size pads should I make for these components?
> I read on the web that the ∗∗ minimum ∗∗ pad should
> include a 5 mil annulus (ring) around the component
> leads. But I don't know what the diameter of the
> leads are for these components. So let me ask you
> what size pads have you found to work well for these
> through-hole parts?

The library package definitions will already define hole sizes. For example,
the transistors already "know" that the TO92 holes should 32 mil. Be
generous with pad restring since you're drilling manually. Allow yourself at
least half the drill radius. My default rule set has 70%, I think, and a
large enough max size to accommodate.

Set your drill sizes with Options|Set|Drill. Just click OK to accept the
sizes. Run drill-legend.ulp to create and populate a drill legend layer.

Pulsar www.pulsar.gs sells a white film that sticks to the toner, to
simulate white silkscreen. Transfer the silkscreen toner to the etched
board, and then laminate the white transfer sheet.