History of Precise Reading applied to Electrical Measuring Instruments

Focusing on the Diagonal Scale

Abstract

Analog Indicating Electrical Instruments were developed in the last half of the nineteenth century. Having searched for the source of precision readings in the measuring such as astrolabes, Tyco's quadrant or surveyng instruments which employed nonious scales, diagonal scales and micrometer driven scales in Europe, the US and Japan from the fourteenth century, the author found that Edward Weston in the US employed diagonal scales for the precision electrical meters.
Through the reproduction of old hand-drawing method of Electrical Instruments Scales which have diagonal graduations, he concluded that the diagonal scales were the most appropriate measure for precision analog electrical meters.