UltraCAD Design, Inc

Articles on
Trace Current/Temperature/Power/Resistance



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How Many Volts IS This: The RMS Role  
  Confused about what RMS  voltage means? You're not the only one, as you'll find out when you read this article, from the July 2001, issue.
Temperature Rise in PCB Traces.   
  This rather technical paper appeared in the Proceedings of the PCB West Design Conference  March 23-27, 1998. It looks at the relationship between trace configuration, current, and temperature rise in PCB traces and is based on two data sources --- the graphs we are all familiar with in IPC-D-275 and another article that appeared in Design News back in 1968. It is one of Brooks' most distributed articles and is presented at least yearly at PCB design conferences. See also our new PCB Trace Calculator and our new video based on Brooks' seminar.
Fusing Current: When Traces Melt Without a Trace!  
  After reading "Temperature Rise in PCB Traces," someone asked me: "I have a trace that must carry 10 amps for one-half second. Then I don't care what happens to the board. How big a trace do I need?" We found some interesting formulas that related to this question and prepared this article that ran in the December, 1998, issue of the magazine.
Gauging Traces.    
  What is the relationship between AWG wire gauge and trace size? This article, from the January, 2001 issue, explains the relationship and provides a formula for conversion. See also our new companion calculator for making these calculations easier. (Note: This article was revised 7/01 to correct an error in one of the formulas.)
IPC Trace/Temperature Curves  
 We have included here for convenience reprints of the historical trace current/temperature curves we are all so familiar with.
Current Carrying Capacity of Vias; Some Conceptual Observations  
This article was in response to the many questions we receive asking how the current carrying capacity of traces relates to vias that might be along them.
Skin Effect
            The skin effect is the tendency of high frequency current density to be highest at the surface of
            a  conductor and then to decay exponentially toward the center. Its effect is to reduce the effective
            cross sectional area of a trace, which in turn increases its resistance and reduces its current carrying

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