The Birth of Transmission Line Theory

How the 1858 Transatlantic Telegraph Advanced Electromagnetism

A marvelous video from Visual Electric.

The key to understanding modern transmission line theory is to first understand its history. This is the story of how the first Transatlantic Telegraph Cable in 1858 led to the birth of Transmission Line Theory. Professor William Thomson (later Lord Kelvin) was the genius who developed the initial breakthrough that led to the first accurate model of a long cable. Although it would be left to Oliver Heaviside some decades later to introduce inductance, Kelvin's idea to distribute the resistance and capacitance evenly along the line led to a powerful mathematical analysis with enough predictive power to explain the failure of the first transatlantic cable. The mathematics of Lord Kelvin's analysis is fascinating - and crucial to understanding how modern transmission theory was developed.

• 00:00 Introduction

• 00:39 Motivation

• 01:53 A primitive starting point

• 02:58 Description of Kelvin's model

• 09:41 The first transatlantic cable

• 11:32 Lord Kelvin rises