Board Etch Run Impedance Calculator

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This tutorial discusses the calculations and formulas associated with determining the board etch run impedance based on the thickness of the copper board run, dielectric constant, trace run width, and substrate height. The disciplines of Electrical Engineering and Physics, particularly electromagnetism, are crucial to understanding this content.

In electrical engineering and particularly in the design of printed circuit boards (PCBs), the impedance of the board etch run plays a critical role. The board etch run refers to the conducting path formed on the board after the etching process. Its impedance, or resistance to the flow of electrical current, is determined by factors such as the thickness of the copper board run, the dielectric constant of the material, the width of the trace run, and the height of the substrate. This tutorial will guide you through the calculations needed to determine this impedance. Understanding this topic involves the field of physics, specifically electromagnetism.

Board Etch Run Impedance Calculator
Board Etch Run Impedance Calculator Results
Effective Dielectric Constant =
Effective Trace Run Width = mil
Effective Substrate Height = mil
Impedance = ohm

Example Formula

The formula for calculating the board etch run impedance is:

Z0 = {87 / sqrt[(1.41 + (T / H)) × (εr + 1.41)]} × log10[5.98 × H / (0.8W + T)]
  1. Z0: The characteristic impedance of the board etch run, measured in ohms (Ω).
  2. T: The thickness of the copper board run, measured in inches.
  3. H: The height of the substrate, measured in inches.
  4. εr: The dielectric constant of the material.
  5. W: The width of the trace run, measured in inches.

Impact on Society

The accurate calculation of board etch run impedance has led to vast improvements in electrical device performance and reliability. High-frequency signals, such as those used in radio and telecommunications devices, rely heavily on precisely calculated impedance to ensure signal integrity. Furthermore, these principles have influenced the development and design of various technologies, from smartphones and GPS devices to advanced medical equipment.

Real Life Application in Industry

The principles and calculations explained here are applied in various industries. They are most commonly used in the manufacturing of printed circuit boards (PCBs) for a wide range of electronic devices, including computers, smartphones, and automotive systems.

Key Individuals in the Discipline

The specific formula for calculating the impedance of a board etch run has no single attributed author, as it is a fundamental principle derived from Maxwell's equations of electromagnetism. However, significant contributors to the field of electrical engineering, such as Michael Faraday and James Clerk Maxwell, have laid the groundwork for understanding electromagnetic phenomena, including impedance.

Interesting Facts

  1. The discipline of these calculations extends into high-speed and high-frequency circuit design, which is essential in modern telecommunications.
  2. Impedance mismatching can lead to reflection of signals, causing data loss and reducing the performance of electronic devices.
  3. The evolution of PCB manufacturing and design, in part through understanding impedance calculations, has revolutionized the technology industry and contributed to the miniaturization of electronics.


Understanding the calculation of board etch run impedance is fundamental to the design and manufacture of printed circuit boards. This understanding aids in enhancing the performance of electronic devices across various industries and contributes significantly to the continuous evolution of technology.