Willoughby Smith

Who was Willoughby Smith?

Willoughby Smith was an English electrical engineer who discovered the photoconductivity of the element selenium. This discovery led to the invention of photoelectric cells, including those used in the earliest television systems.

In 1848, he began working for the Gutta Percha Company, London where he developed iron and copper wires insulated with gutta-percha to be used for telegraph wires. In 1849, Smith superintended the manufacture and laying of 30 miles of underwater telegraph wire from Dover to Calais. He worked closely with Charles Wheatstone who had designed the machinery for making and laying the cable.

The project was a success and over the following decades, Smith and the company he worked for were involved with many other underwater telegraph cable projects.

In 1873. Smith developed a method for continually testing an underwater cable as it was being laid. For his test circuit, he needed a semi-conducting material with a high resistance and selected selenium rods for this purpose.

The selenium seemed to do the job properly, except in actual use, the device gave inconsistent results.