Series Availability
EA , ED , EK , EP

General Description
This option provides the same conformable soft copper lead ribbons as used in Option L , but with the addition of a 1-mil [0.001-in (0.025-mm)] thick encapsulation layer of polyimide film. The encapsulation layer provides excellent protection for the gage during handling and installation. It also contributes greatly to environmental protection, though supplementary coatings are still recommended for field use. Gages with Option LE will normally show better long-term stability than open-faced gages which are "waterproofed" only after installation. A good part of the reason for this is that the encapsulation layer prevents contamination of the grid surface from fingerprints or other agents during handling and installation. The presence of such contaminants will cause some loss in gage stability, even though the gage is subsequently coated with protective compounds.

Leads
Nominal ribbon size for most gages is 0.012 wide x 0.004 in thick (0.30 x 0.10 mm) copper ribbons. Leads are approximately 0.8 in (20 mm) long. See also leadwire orientations .

Solder
+430 deg F (+220 deg C) tin-silver alloy.

Temperature Limit
+400 deg F (+200 deg C).

Grid Protection
Entire gage is encapsulated. A short extension of the backing is left uncovered at the leadwire end to prevent contact between the leadwires and the specimen surface.

Fatigue Life
Fatigue life will normally be degraded by Option LE. This occurs primarily because the copper ribbon has limited cyclic endurance. Option LE is not often recommended for very high endurance gages such as the ED Series .

Size
Matrix size is unchanged.

Strain Range
Strain range will usually be reduced by the addition of Option LE.

Flexibility
Gages with Option LE are not as conformable as standard gages.

Resistance Tolerance
Resistance tolerance is normally doubled by the addition of Option LE.

Reference Table