Edward E. Simmons and Arthur C. Ruge

Strain gauge

The strain gauge is a bonded metallic foil sensor that translates mechanical strain into resistance change via conductor geometry. Invented independently in 1938 by Simmons (for shock-load metallurgy) and Ruge (for seismological water tank modelling), it solved measurement gaps where optical methods failed. It works reliably within elastic limits—but fails without precise adhesion or thermal control. Its legacy is not novelty but adoption: it became the standard interface between force and electronics because it was simple, scalable, and grounded in first principles—not hype.