The Heat Sink Effect of Printed Conductors

The conductors on a printed wiring board can play a significant role in removing heat from electrical components. This paper describes a method of estimating the impact such conductors have on component temperatures. It provides a series of equations and charts for estimating the thermal resistance from one end of a conductor, through the major heat paths to the ambient. The analysis accounts for the effects of temperature gradients within the conductor and within the board. Curves of thermal resistance for typical printed wiring board conductors in a natural convection environment are given. An example problem is also given and the result, using the charts, is compared to the result obtained using a finite difference computer solution. Agreement from the two approaches is within 4 percent.