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I. Introduction & Description
The PRF-922B Miniature Two-Point Resistance Fixture Set accurately measures surface resistance of small areas. It consists of a PRF-922B Two-Point Resistance Fixture assembly, shielded cable equipped with BNC connectors; probe cover, and a BNC to male banana adapter.
The PRF-922B works in conjunction with a wide range resistance instrument, such as the Prostat PRS-801 Resistance System, PRS-812 Resistance Meter, or ESD Check ESI-870 Resistance Indicator, and an insulated test bed. This instrument and fixture combination provides direct point-to-point resistance measurements in ohms across the surface of small parts and assemblies. |
A. PRF-922B Two-Point Resistance Fixture Description
This precision fixture consists of 2 gold plated, spring-loaded contact electrodes spaced 0.250 inches (6.35mm) apart, center-to-center. The electronic quality gold plated contact probes are 0.1-inch (2.54mm) in diameter, and are supplied with conductive synthetic rubber contact boots, which are 0.125-inch (3.18mm) diameter. The conductive boots are used to reduce contact resistance between the gold contact probes and materials under test in certain applications.
- The resistance measurement range of the PRF-922B fixture is 0.9 ohms at <10 volts to 1.0E+12 (1.0x1012) ohms at 100 volts.
- Contacts are pogo-pin type ATE quality probes made of beryllium Copper, coated with 60 micro inch of hard Gold. Spacing allows for measurement of items with surfaces approximately 0.125 inches wide having a length of 0.32 inches or larger.
- The contact assembly’s outer housing incorporates “stops” that insure consistent contact pressure during measurement.
- Overall size of the PRF-922B is 0.50 inches in diameter by 7.0 inches (178 mm) long. This optimal size and shape make the fixture very comfortable and easy to handle. Its outer housing is made of black anodized aluminum.
II. Cautions & Warnings
As with any electrical device, use proper electrical precautions and measurement practices to avoid personnel shock. Read this manual in its entirety before attempting to use these products.
NOTE: This manual displays Cautions and Warnings alerting the user to hazardous operation and servicing conditions. CAUTION or WARNING headings throughout this publication flag this information, where appropriate. Follow all Caution and Warning instructions at all times.
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III. PRF-922B Micro Probe & PRV-913B Verifier Operations
- PRF-922B Setup
- Connect measurement cable to PRF-922B
- Remove black rubber protective cover from PRF-922B’s BNC connection.
- Attach shielded cable to the probe’s BNC connection (Figure 2).
- Connect measurement cable to Dual Banana BNC Converter (Figure 3)
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- Once the cable and BNC adapter are installed the PRF-922B is ready for continuity test, verification and use (Figure 4).
- To use, connect dual banana converter to wide range, resistance instrument with ¾ inch terminal spacing. Flange side of dual banana should be connected to the Positive (+) power terminal.
NOTE: To remove BNC connections, apply slight pressure and twist connector counter clockwise.
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C. PRF-922B Verification Using the PRV-913B Two-Point verification fixture
- Connect the BNC/banana adapter to the wide range, resistance measurement instrument. Flange side of dual banana should be connected to the Positive (+) power terminal. This applies test voltage to the 10 outer ring electrodes.
- Remove PRF-922B Probe Cover (Figure 5).
- Position PRF-922B vertically into the PRV-913B Two-Point Verifier with its spring loaded pin electrodes making direct contact with the Verifier’s gold plated test segments.
- Depending on your resistance instrument select either 10V or 100V test voltage.
- Measure PRF-922B probe resistance while positioned in the PRV-913B Two-Point Verifier. Resistance should be 1.0x10 ohms ±5%.
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D. Basic Measurements Using the PRF-922B Micro Probe
- Place material to be measured on an insulated test bed, the clean insulated surface (Black, labeled side) of the PTB-920, or an insulated acrylic plate.
- Position the PRF-922B vertically directly over test area and lower it until the spring loaded center electrode makes direct contact with the material under test.
- Apply sufficient pressure on the probe until the center and outer spring loaded electrode are partially compressed while in contact with the test material.
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IMPORTANT NOTE
Adjust probe pressure to insure that the electrode springs are controlling the probe’s connection with the material’s surface and that the springs are not fully compressed against their stops. This will insure reproducible measurements.
- Select appropriate instrument test voltage and initiate resistance measurement. ESD Association S11.11 test voltage guidelines for measuring packaging materials are as follows:
- For material resistance measurements of less than 1.0x104 ohms, use <10 volts.
- For measurements of 1.0x104 to <1.0x106 ohms, use 10 volts.
- For measurements greater than 1.0x106 ohms, use 100 volts
NOTE: For optimal performance and accuracy, use the Prostat PRS-801 Resistance System in its AUTOMATIC Mode (either Default Mode 1 [Ohms], or Mode 2 [Exponential 1.0EXX/Ohms] display). AUTOMATIC Mode will control test voltage, resistance range adjustment and electrification period automatically. |