Prostat Corporation
PRF-912B Miniature Concentric Ring
Precision resistance measurement of small areas up to 1.0 x 1012 ohms.
  • Measures Surface Resistance from 0.9Ω to 1.0x1012Ω
  • Approximates Measurements Typically Obtained when using ANSI/ESD STM11.11
  • Spacing Allows for Measurement Area of 0.32 inches (8.13mm)
  • Spring Loaded Center Electrode Surrounded by 10 Contact Electrodes
  • Includes Conductive Rubber Covers
  • Certificate of Calibration Traceable to NIST included



Measuring Surface Resistance up to 1.0x1012 ohms
The PRF-912B accurately measures surface resistance of small areas up to 1.0x1012 ohms. It consists of a PRF-912B Concentric Resistance Fixture, shielded cable equipped with a BNC connectors, and red and black banana jack to efficiently connect to any of the Prostat's resistance meters.

Approximates Surface Resistance Measurements Similar to ANSI/ESD STM11.11
The PRF-912B is designed in miniature to approximate surface resistance measurements typically obtained with the ANSI/ESD STM11.11 Surface Resistance Standard fixture. The PRF-912B, however, is approximately 1/10th the size of the ANSI/ESD STM11.11 fixture. Based on its size the PRF-912B is often referred to as a Miniature Concentric Ring.

To obtain an estimate of ASTM D-257 Surface Resistivity in ohms/square, simply multiply the PRF-912B fixture measurement by 10 (i.e., add one order of magnitude).

Use it with any of Prostat's Resistance Meters
The PRF-912B is designed to work in conjunction with a precision wide range resistance instrument, such as the PRS-801B Resistance System, and an insulated test bed such as the PTB-920.

Spring Loaded Gold Plated Pins
The miniature concentric fixture consists of a spring loaded 0.10 inch (2.54 mm) diameter center electrode surrounded by 10 each 0.06 inch (1.5 mm) diameter contact electrodes that electrically form a continuous outer ring.

Use it with the Conductive Rubber Ring and Boot
The ensure good contact with irregular surfaces is obtained, use the included removable conductive cover for the center electrode and the conductive ring for the 10 outer pins. This allows you to make measurements with either the gold plated electrode contacts, or via conductive rubber covers. The rubber boot and ring resistance is less than 2 ohms, minimizing contact resistance and providing accurate measurements.

To order additional rubber boots and ring, refer to model PRF-MR55.