This fixture is intended to be used with an ordinary battery-powered multimeter to quickly and conveniently perform "surface" or "sheet"-resistance measurements on specimens of tapes, films, composites, fabrics, and other flat materials. The unguarded electrode arrangement is consistent with the specifications of ASTM D257 FIG 3, ASTM D4496, DIN-IEC 60167, and 60093, and IEC 62631-3-3.
The extent to which measurements made with the fixture can be certified to be compliant with these standards depends upon the resistance range of interest. Materials sold or used by coaters, laminators, convertors, and other suppliers of tapes and membranous materials for electrical and electronic applications are typically categorized as conductive, 10-10^5 ohm·cm, static dissipative, 10^5-10^12 ohm·cm, and insulative, >10^12 ohm·cm. Standard multimeters, such as the Fluke Model 114 we offer, have a usable range of 10 to about 5x10^7 ohms, with an accuracy of ±2%, and so may be used with our fixture for certifying products in the first two categories but not the third, insulative materials. An exception may have to be taken regarding the voltage applied to make the measurement as well. ASTM D 247, for example, calls for the applied voltage to be 500V. The report must indicate the measurement was made instead using an applied voltage of 9V.
.
The fixture consists of a pair of 1.5in/38mm wide x 0.75in/19mm deep copper electrodes mounted on a 3/8in-thick insulating polycarbonate plate, spaced opposite one-another at a distance equal to their width. Standard banana-jack binding posts are provided by which the electrodes may be connected to the terminals of the multimeter using the included banana-jack-type test leads.
The measurement is performed by simply placing the unit on the specimen placed upon a smooth, flat surface. The resistance indicated after one minute is reported as the surface resistance or sheet resistance of that surface. No calculation is required. The value may be expressed in units of ohms (Ω) or "ohms per square" (Ω/sq), depending on individual preference or accepted practice within the user's organization.
The extent to which measurements made with the fixture can be certified to be compliant with these standards depends upon the resistance range of interest. Materials sold or used by coaters, laminators, convertors, and other suppliers of tapes and membranous materials for electrical and electronic applications are typically categorized as conductive, 10-10^5 ohm·cm, static dissipative, 10^5-10^12 ohm·cm, and insulative, >10^12 ohm·cm. Standard multimeters, such as the Fluke Model 114 we offer, have a usable range of 10 to about 5x10^7 ohms, with an accuracy of ±2%, and so may be used with our fixture for certifying products in the first two categories but not the third, insulative materials. An exception may have to be taken regarding the voltage applied to make the measurement as well. ASTM D 247, for example, calls for the applied voltage to be 500V. The report must indicate the measurement was made instead using an applied voltage of 9V.
.
The fixture consists of a pair of 1.5in/38mm wide x 0.75in/19mm deep copper electrodes mounted on a 3/8in-thick insulating polycarbonate plate, spaced opposite one-another at a distance equal to their width. Standard banana-jack binding posts are provided by which the electrodes may be connected to the terminals of the multimeter using the included banana-jack-type test leads.
The measurement is performed by simply placing the unit on the specimen placed upon a smooth, flat surface. The resistance indicated after one minute is reported as the surface resistance or sheet resistance of that surface. No calculation is required. The value may be expressed in units of ohms (Ω) or "ohms per square" (Ω/sq), depending on individual preference or accepted practice within the user's organization.