Don't press the limits when making your first board. As experience
builds you will learn just how fine your construction techniques can go.
I've seen commerically prepared boards, intended for amateur
construction, with extremely small through hole pads. This invites
builders with limited experience, and big soldering irons, to lift traces.
When making simple through hole boards my basic rule is to make
everything big. I like .080 diameter pads, they provide enough
clearance to avoid contact between two .100 spaced pins. This gives
plenty of soldering surface and reduces chances of lifting the pad
with heat. For simple boards like this I also like traces .050 wide.
These are very forgiving of excess etching. Why etch away more
copper than you need to?
Leave the hole in the pad center so the drill can center on the etched
out hole.
If you pass traces between .100 spaced pins the pads need to be
reduced. I reduce the pad size, make it rectangular, and generally
use about a .015 wide trace between the pins.
The whole design concept changes when making surface mount boards.
Much less surface area, and less soldering heat, is required when you
don't pass a wire through the board.
--- In Homebrew_PCBs@yahoogroups.com, "alan00463" <alan00463@y...> wrote:
>
> 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?
>
> Alan
>