I claim the ornamental design for an electric measuring device, as shown and described herein.
FIG. 1 is a perspective view of the electric measuring device showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines appearing in the drawings are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.