Description

Photograph of an audion lying on top of a copy of the the patent issued for it in 1907. The document indicates that L. De Forest filed an application for a "device for amplifying feeble electrical currents" on October 25 1906. The device was patented January 15, 1907. Original caption: "An Industry Is Born. With a half century of significant developments to its credit, the electronics industry can trace its origin to the invention of the Audion of Lee DeForest in the latter half of 1906, and particularly to the patent, issued January 15, 1907, for a 'device for amplifying feeble electrical currents.'" Used in: Technology Review, June 1957, p. 138.