PRF-911 Concentric Ring Set
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  • PRF-911 Concentric Ring Set
    Measure Surface & Volume Resistance of flat materials
    • Used to design materials for Static Control and other Electrostatic Discharge (ESD) applications
    • Necessary for the Qualification and Verification of ESD Controlled Packaging Materials to meet current standards
    • Measures Surface Resistance per ANSI/ESD STM11.11
    • Measures Volume Resistance per ANSI/ESD STM11.12
    • Approximates Surface & Volume Resistivity per ASTM D-257
    • Incorporates a spring loaded, self-aligning center electrode feature to reduce calibration frequency
    • Its Dual Test Bed consists of an Insulated Test Surface for ANSI/ESD STM11.11 Surface Resistance measurements laminated to a Steel Test Plate used for ANSI/ESD STM 11.12 Volume Resistance measurements
    • Used with a wide range Resistance Meter and one 5 lb. Electrode. (Instrument and Electrode not included)
    Resistance of Conductive, Dissipative, and Insulative Materials
    Measure Surface or Volume Resistance
    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, and Volume Resistance per ANSI/ESD STM11.12, 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
    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-801 Resistance System, PRS-812 Resistance Meter and the PAS-853B Resistance Auditing System.

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

    Measure Static Control Bags
    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.
    Maintains Consistent Contact
    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.

    This reduces the need for frequent calibration and alignment of the fixture.

    A Dual Test Bed for the either Measurement
    A Dual Test Bed for the either Measurement
    The PTB-920 Dual Test Bed consists of an insulated test surface for S11.11 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
    Wide Range, Accurate Performance
    The PRF-911 is capable of accurate measurements from less than 100 ohms (<1.0x102 ohms), to greater than 1.0x1012 Ohms (>1.0x1013 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.

    Technical Specifications


    Inner electrode disc (D1) outside diameter: 1.2 inches (3.05cm) – Spring Loaded
    counter pressure approximately 2 lb., ± 2 ounces (0.82 Kilograms, ± 0.06 kg)
    Outer electrode ring (D2) inside diameter: 2.25 inches (5.72cm) Width 0.125 inches (0.32cm)


    5.0x105 ± 1% Ohms @100 volts per ANSI/ESD STM11.11 for Surface Measurements
    5.0x105 ± 2% Ohms @10 volts
    5.0x105 ± 1% Ohms @100 volts for Volume Resistivity Measurement
    5.0x105 ± 2% Ohms @10 volts


    6.9 cm2 Total D1 Contact Area. Allows for D1 mounting screw head.


    1.8 lb (0.82 kg) without BNC/Banana adapter or connections.


    Fixture installed BNC for Inner Disc (D1) connection, and fixture assembly ground; dual BNC/Banana plug adapter supplied.
    Fixture installed standard banana receptacle for Outer Ring (D2) connection.


    Diameter: 4.0 inches (10.16 cm). Lamination of 18 inch acrylic plastic and ¼ inch stainless steel, or aluminum plate.


    Not Applicable. The fixture and test bed are used in conjunction with the PRS-801 Resistance System and test leads.


    User Manuals

    Release Date

    2,890 KB

    Data Sheets

    Release Date

    76 KB