Prostat Corporation
PRF-911 Concentric Ring
Measure Surface & Volume Resistance of Planar Materials
  • Measures surface resistance per ANSI/ESD STM11.11
  • Measures volume resistance per ANSI/ESD STM11.12
  • Meets the requirements of IEC 61340-2-3
  • Approximates surface & volume resistivity per ASTM D-257
  • Incorporates a spring loaded, self-aligning center electrode feature to reduce calibration frequency
  • Includes an insulated and metal dual test bed
  • Designed to work with a wide range resistance meter and one 5 lb. electrode
  • Certificate of calibration traceable to NIST included



Measure Surface or Volume Resistance per ANSI/ESD STM11.11 and ANSI/ESD STM11.12
Designed originally for flat (planar) packaging materials, this unique portable test fixture will measure Surface and Volume Resistance of virtually any flat material in accordance with current industry standards. These include Surface Resistance per ANSI/ESD STM11.11, Volume Resistance per ANSI/ESD STM11.12, IEC 61340-2-3 and will approximate surface and volume resistivity measurements per ASTM D-257.

Note that ANSI/ESD Standards are for materials employed for electrostatic discharge control, while ASTM D-257 is used to assess insulating materials utilized in electrical distribution and power applications.

Use it with our Resistance Instruments
The PRF-911 Concentric Ring is a low-profile test fixture conceived specifically for use with the Prostat Resistance instruments such as the PRS-801B Resistance System, PRS-812B Resistance Meter and the PAS-853B Resistance Auditing System.

The Concentric Ring is an important tool to calculate surface resistivity and volume resistivity. For example, multiply the surface resistance measurement in ohms by 10 to obtain surface resistivity in ohms/square.

Measure ESD Bags
Its compact size allows the fixture to be inserted into small flexible containers, such as an ESD protective bag, without having to cut the package. This reduces the need for frequent calibration and alignment of the fixture.

Maintains Consistent Contact
The PRF-911 incorporates a spring loaded, self-aligning center electrode feature. This unusual feature aids in maintaining consistent contact of the fixture’s highly conductive rubber electrode surfaces with materials under test.

A Dual Test Bed for the either Measurement
The PTB-920 Dual Test Bed consists of an insulated test surface for ANSI/ESD STM11.11 surface measurements laminated to a steel test plate, which is employed for volume resistivity measurements. The four inch diameter steel test bed assembly includes a banana receptacle for instrument connections during volume measurements.

Wide Range, Accurate Performance
The PRF-911 is capable of accurate measurements from less than 100 ohms (<1.0x102 ohms), to greater than 1.0×1012 Ohms (>1.0×1013 ohms/square). The fixture is configured so that it can be connected to either an instrument ground reference or earth ground to minimize the effects of extraneous fields and charges on the measurement.