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21May

# PCB circuit board design copper platinum thickness, line width and current relationship

The calculation of PCB current-carrying capacity has been lacking of authoritative technical methods and formulas. Experienced CAD engineers can make more accurate judgment by relying on their personal experience. But for CAD novices, it is not a problem.

The current carrying capacity of PCB depends on the following factors: wire width, wire thickness (copper foil thickness), allowable temperature rise. As we all know, the wider the PCB line, the greater the current carrying capacity. Given the same conditions, 10MIL can withstand 1A, then 50MIL can withstand what current, 5A? The answer, of course, is no. Please take a look at the following data provided by international authorities:

The unit of line width is Inch (1inch=2.54cm=25.4mm).

Data source: MIL-STD-275 Printed Wiring for Electronic Equipment

Second, PCB design copper platinum thickness, line width and current relationship

Before understanding the PCB design copper platinum thickness, line width and current relationship, let's understand the conversion between the PCB copper thickness in ounces, inches and millimeters: "In many data tables, PCB copper thickness is often used in ounces, and its conversion relationship with inches and millimeters is as follows:

1 oz = 0.0014 inches = 0.0356 mm (mm)

2 oz = 0.0028 in = 0.0712 mm (mm)

Ounces are a unit of weight, which can be converted to millimeters because the pcb's copper thickness is ounces per square inch."

PCB design copper platinum thickness, line width and current relationship table

The empirical formula can also be used to calculate :0.15× linewidth (W)=A

The above data are the line current bearing values at the temperature of 25 ° C.

Conductor impedance :0.0005×L/W(line length/line width)

The current bearing value is directly related to the number of components/pads on the line and through holes

In addition, the current bearing value of the wire is related to the number of holes in the wire

Wire current bearing value and the number of wire wire hole welding pad exists a direct relationship (at present did not find the welding pad and hole aperture per square millimeter on the line bearing value of the calculation formula, have a heart of friends can find their own, personal is not too clear, not to explain) here only to do some simple influence on the line current bearing value of the main factors.

1. The bearing value listed in the table data is the maximum current bearing value that can be borne at room temperature of 25 degrees. Therefore, various factors such as environment, manufacturing process, plate process, plate quality and so on should be considered in the actual design. So the table is provided only as a reference value.