Carrying Capacity in Printed Circuits

One important consideration when designing electronics is to ensure that the electrical components operate at temperatures that will maintain long life and be reliable. Current carrying capacity of the printed circuit board traces is apart of managing the board tenperature, which directly impacts the components. (A trace is a copper conductor in a printed circuit board.The terms conductor and trace are used interchangeably for a printed circuit throughout this chapter. Track is another common term for trace or conductor.) Properly sizing the traces for current is necessary to achieve the desired temperature rise at the board level. 

Five different charts are presented in this chapter. The first has been arotmd since the beginning of the printed circuit industry and is intended for external traces. The second is for sizing internal traces. The third and fourth are for internal and external traces. These are from more recent studies and are referred to as baseline charts. The fifth is used with the baseline charts to account for the heat spreading and cooling effect when copper planes exist in the board. Even with these charts, there are times when charts alone do not offer enough information and analysis tools must be used to solve current carrying capacity problems. 

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