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How much current can a PCB handle?

E

Eeyore

Jan 1, 1970
0
John said:
Spacing; nothing about current capacity of traces and sheets.

Right, I'm thinking of some old BS we had an extract from.

Graham
 
P

przemek klosowski

Jan 1, 1970
0
How much current can different copper weight PCBs handle? Not so much in
terms of how much can traces handle, but a PCB in general. I'm talking
strictly DC current, relatively low voltage (+24VDC).

http://64.233.179.104/translate_c?h....tech-chat.de/shunt.html&prev=/language_tools

Andreas Weber (author of AAcircuit) did measurements on a test PCB with
..1" traces. He showed resistivity data, which seemed to go linear up to
10 A, and then show resistivity increase due to self-heating. I fitted
his data and got 0.010 Ohm resistance for his traces and 35+-15 K/W
thermal resistance for a zig-zagging shunt about 1.3 inch long and .1 inch
wide on a plain PCB (he doesn't give much detail--I assume standard 1 oz)

The formula I used was U = R*I*(1+.0039*Rtherm*R*I.^2) where U and I
are measured voltage and current, R is the ohmic resistance, .0039
is resistivity thermal coefficent of copper and Rtherm is the thermal
resistance of this particular PCB trace configuration
 
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