PCB Track width

No, but try google:

Trace Width Javascript calculator:

Which is the best?

Scott

--

DIY Piezo-Gyro, PCB Drill Bot & More Soon!

POLITICS, n. A strife of interests masquerading as a contest of principles. The conduct of public affairs for private advantage. - Ambrose Bierce

There is no giant behind the devastation of the world?only a shriveled creature with the wizened face of a child who is out to blow up the kitchen because he cannot steal his cookies and eat them, too. - Ayn Rand

--- Somone has that info posted on the web somewhere, and there may even be a calculator for it, but in case you can't find them, I posted a graph for you on abse under the same heading as this thread.

A solder mask _won't_ improve the current handling capability because it'll provide a thermal barrier between the trace and ambient air, which will restrict heat removal by convection, causing it to run hotter than if it was uncovered. However, it's not a good idea not to use a soldermask since it will protect the traces from solder bridges and oxidation. Besides, looking at the chart you can see that if you use 1oz copper and you specify 0.015" wide traces you can expect a temperature rise of about 10°C over ambient with about 1A going through the trace. For power traces you should use something like at least 0.06" wide traces, so that puts the temp rise down in the noise. Specify a double sided board with plated-through holes, nice wide traces, Solder Mask Over Bare Copper, (SMOBC) and 2oz copper if you're not very experienced with PCB fabrication and you expect to be doing a little rework, and you'll wind up with a nice looking board which you can take some liberties with and not beat to death if you make a mistake or two.

-- John Fields

First you need to find the maximum current density that the board can carry. Then find out the thickness of the copper. Then you can (trivially) calculate the required width.

Dwayne

A soldermask is some plastic to cover the copper tracks such that there won't be any tin. It has no influence on the current handling capability.

for the individual LEDs I'd use 20mil tracks and for the combined perhaps a 60mil one.

Rene

google on: "temperature pcb" in the All words field, and "track width" in the exact phrase field.

Regards Ian

Now do the calculation when you have peak currents of over 50 Amps such as in high power audio ! 20A rms isn't uncommon on a pcb and it's nice to know you don't need a track 20mm wide ( and what the temp rise will be ).

I have a similar guide somewhere based on a British Standard IIRC. Thankfully it's in metric ( none of that US 'square mils' nonsence ).

Graham

Thanks Ian, I was aware of these calculations. Why should a track be made as thin as possible to have maximum temperature rise ? From my selfetching days, I still try to avoid tracks and distances below 15mils when the space is there. Actually since doing precision analog, I calculate the microVolts lost over a few inches of tracks when passing milliAmps.

Rene

In practice 2 oz is widely used ( 70 um ). The 20A rms is not a continuous figure thankfully with audio.

Graham

True. That would be a case for 3 to 10 ounce copper then. Equivalent to 100 to 300um thickness.

Rene

Hi Rene:

I was sure you would know these resources, I was giving a pointer to the OP, and wanted to keep your response as the alternative engineering "this works" approach.

Regards Ian

and by precluding plating, it delivers a higher resistance_per_unit_length than unmasked/plated tracks.