A BEGINNER’S INTRODUCTION TO PCB TRACE IMPEDANCE - CONT'D


Program Description:   What is impedance anyway, what causes it, why does it matter and what happens if we get it wrong? This entry level presentation describes the component properties of a PCB trace (a transmission line) that come together to determine the impedance. Maybe surprisingly, you experience impedance in various other forms every day. But you never thought of it that way. So we’ll begin by briefly identifying and acknowledging some of those experiences, then relate them to the electrical transmission line. Next we’ll look at the transmitted signal as it progresses from the signal source into the line, and what happens when it eventually reaches the end of the line – depending on how the line is terminated; open/short/matched/mismatched. And we can discuss why fabricators often don’t use the same Er (Relative Permittivity, often called Dielectric Constant, sometimes Dk) And throughout, we’ll keep the subject light and the mathematics simple; If there is time at the end we can briefly review the frequency dependent problems of dielectric loss (signal energy lost to the line’s surrounding environment) and copper loss (signal energy lost to the copper conductor.) But we’ll still keep it simple.

Speaker:  Ken Taylor ~ POLAR INSTRUMENTS

About this Speaker:  Ken Taylor never designed a board in his life, nor did he build one. And he’s too old to begin now. He began his working career teaching high school and college,and after 25 years of international sales and marketing with Tektronix, he has managed Polar Instruments US operations. Notwithstanding, he understands the physics PCB transmission line impedance and has worked with engineers, board designers and board manufacturers during his entire Polar career. His teaching experience helps him convey concepts in a non-threatening way.

E-Mail this Speaker with pre-talk questions or suggestions: dgdirect@polarinstruments.com