topic Re: Deciding Trace width for two layer PCB in EAGLE Forum

Deciding Trace width for two layer PCB

Anonymous — Mon, 11 Dec 2017 10:54:44 GMT

I have created a schematic which uses 12V and 5V power lines (these tracks also used for pulsing the stepper motor) and the whole circuit consumes a current of 100mA - 200mA. I am using two layer board. What are the factors I have to look into for creating a good trace width? Your help would be much appreciated.

Thanks in advance.

Re: Deciding Trace width for two layer PCB

jorge_garcia — Mon, 11 Dec 2017 20:07:59 GMT

Hello @Anonymous,

I hope you're doing well. The IPC has formulas for the current carrying capacity of copper. Google the Saturn PCB Toolkit and you'll find a really good PCB calculator that can calculate this and other parameters.

If you need an OK answer now, radio amateurs the following rule of thumb: For every 500mA amps of current, trace thickness increases by 10 mils. So if you need a trace to carry 1AMP you would use a 20mil trace. This rule holds up to about 4Amps of current when compared with the IPC guidelines.

It's important to think about the MAXIMUM current a trace will current and make sure the trace you use is sized properly to conduct it.

Please let me know if there's anything else I can do for you.

Best Regards,

Re: Deciding Trace width for two layer PCB

Anonymous — Wed, 13 Dec 2017 12:00:10 GMT

Hi Jorge

Thanks for your help. I am working on it and let you know if I got any questions. I will accept a solution once it done.

Could you please able to help me with this, I need to make a slot/hole like a file attached. It doesn't need any electrical connection. The slot is just for the support. I can see only the hole option is available in the eagle.

Could you please provide me suggestions.

Thanks in advance.

Re: Deciding Trace width for two layer PCB

edwin.robledo — Wed, 13 Dec 2017 14:59:00 GMT

Hi dhinesh.ganesan,

I hope you are doing well upon reading this response, and would like to thank you for your forum participation. At this time EAGLE doesn't support slots, but this is very high on the road map. There are a few option you can consider, use the HOLE command and place 2 hole slightly overlapping each . This will generate many DRC error which can be flagged as accepted. Another option, my preference, is to use the Wire command with the appropriate width and draw the slot on the Milling layer. During your post process (Gerber Files) create a Gerber file only for the milling layer enabled, and instruct the board house this layers is for all your slots.

EAGLE includes a CAM Job called gerb274x-mill-drill.cam which includes a section only for the milling layer.

I hope this helps.

Please 'accept as solution' if my reply resolves your issue.

Best Regards,

Re: Deciding Trace width for two layer PCB

Anonymous — Thu, 14 Dec 2017 12:49:57 GMT

Hi Edwin

Excellent. Thanks for your help.