Donovan Parks wrote:

> In the same vein, can I put 20A though a throughhole with a pin (i.e. through the leg of my MOSFET from on side of the board to the other) without taking special precautions? I realize I can't put 20A through a simple via, but am not sure if I can do it with a throughole with a pin in it.


For reliability it will really be worth using
a plated through hole board, you get 4x the solder
contact to the pin and much better protection
from thermal expansion etc. If you must use single
sided PCB, run 10 mm of leg through the board, bend
it flat and solder it flat across 8mm of the track.

I suspect this will be in a small *sealed* container,
ambient is going to be hot. You really want to
keep temp rise as low as possible. If you can't
use a thicker track why not leave the solder mask
off that track so when it's tinned it will carry
a lot more current, and you can add a decent bead
of solder to the top giving a very thick trace.
This is common in microwave oven PCBs and saves
the hassle of soldering extra wires on top.

Solder gets soft as it gets over 100' and repeated
thermal expansion and soft solder caused many of
the TV faults i've fixed over the years. I've
always had a thermometer on my workbench and any
component leg running over 60'C TOTAL TEMP will
eventually fail and dry-joint often within a year
or two, with a plated through hole you can risk
70'C. I wouldn't even consider running a soldered
component leg at >80'C, especially in a sealed
container that will be annoying to repair. :o)
-Roman

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