On August 10, 1937, George D. Beauchamp received U.S. Patent No. 2,089,171, on an Electrical Stringed Musial Instrument:

Beauchamp and his partner Adolph Rickenbacher started producing guitars according to this design in 1932, incorporating as Ro-Pat-In Corporation (Electro Patent Instruments), later renamed to Electro String Instrument Corporation, and finally to Rickenbacker.

This is generally regarded as the first patent on an electric guitar pickup, but while Beauchamp has received the bulk of the credit, the reality is complicated, and there were others who work working on making electric stringed instruments a reality.

Arthur J. Stimson in one of those “others,”