6242D (0.001 Ω to 1 GΩ)

  • Resistance and Temperature Applications
  • Range 0.001 Ω to 1 GΩ
  • Best Accuracy < 0.1 ppm with Optional 0.03 ppm
  • Ratio Self-Calibration
  • System Integration with Measurements International (MI) Matrix Scanners and High Current Range Extenders
  • Make MI Your Partner in ISO 17025 Accreditation Through Coaching, System Design, Implementation, Calibration Services, Documentation Support and Ongoing Expert Support
Features & Benefits

Since its inception in 1987, MI has been providing customers with the best in resistance measuring equipment. As the original manufacturer of the Automated Direct Current Comparator (DCC) Resistance Bridge, MI has been the industry leader in providing the highest level of automated resistance bridges and turn-key systems to metrology laboratories worldwide.

The AccuBridge® 6242D (furthermore 6242D) is ideal for measurements in both resistance metrology and temperature thermometer applications. With its innovative technology, the 6242D’s speed, measurement accuracy, and data handling capabilities make it the preferred primary resistance measurement system in primary and calibration labs worldwide. The 6242D is designed for flexibility and ease of use.

Ratio Range & Accuracy

The 6242D DCC with its binary wound current comparator technology balances the current ratio with an effective resolution of 25-bit. It provides ratio measurements with an accuracy to better than 100 ppb with a  linearity of better than 5 ppb. The 6242D can perform ratio measurements (Rx/Rs) with resistances valued from 0.001 Ω to 1 GΩ range. A line of optional high current range extenders permits measurements down to 1 μΩ for shunt resistance or direct-current current transformer (DCCT) measurement applications.

Automated Resistance Operation

The 6242D Bridge itself can ratio a standard resistor with another resistor being tested. Optional 10-, 16- or 20-channel scanners can be used individually or together to connect to up to 40-channels of ratio measurement for up to 40 different test resistors.

The 6242D is perfectly suited for front panel operation, or you can team it with MI’s 6242D-SW Windows®-based operating software for fully automated measurements, history logging, graphing, and regression analysis. Front panel operation with the 6242D’s touch-sensitive display panel provides full-bridge capabilities to the operator. The ratio or direct resistance measurements can be made. Multiple measurements over time can be numerically displayed or graphically displayed to best fit your needs.

The AccuBridge® Family of Bridges

The 6242D is a high-performance model MI Bridge. It is one of a family of bridges where there are various bridges optimized for different tasks from measuring Quantum Hall Resistance Standards (QHR) over a smaller range of resistance but with excellent uncertainties, to others which are a better fit for other labs with a broader range of measurements but with larger uncertainties. Three different bridge designs use different measurement methods to measure over 21 orders of magnitude of resistance, from 1 μΩ to 10 PΩ. The AccuBridge® family offers the best line of bridges available for measuring the widest range of resistance.


The 6242D measures both ratio and absolute values. You select functions using the menu on the 6242D’s large touch screen display. For absolute measurements, you enter the value and related uncertainty of the standard resistor using the display’s keypad. You enter the measurement functions such as current through the unknown resistor, settle time, number of measurements, and number of statistics the same way.

The 6242D’s low-noise, touch-screen display is interactive with the measurements, as shown in the screen images below. When a reading is complete, the average value and uncertainty (based on the number for statistics) are displayed. All uncertainty calculations are 2 sigma level.

Summary Tab
The Summary tab displays current measurement data

Table Tab
The Table tab displays a chronological list of measurement data

Graph Tab
The Graph tab displays a graphical representation of the data

Measurement Info Tab
The Measurement Information tab displays measurement parameters

Measurements International provides world-class expertise in DC resistance metrology to National Measurement Institutes (NMIs) primary, and calibration laboratories who need to achieve the lowest possible traceable uncertainty in their measurements and calibration equipment. As your accreditation and global support partner, MI helps ensure your competitive advantage by offering leading product knowledge and applications expertise through coaching, system design, implementation, calibration services, and ongoing expert support.

At MI, it’s not only about the equipment and science; it’s about what you can do and the ease with which you can do it.

Automatic current reversal ensures that DC offsets and thermals are cancelled out during the measurement. The 6242D has a standard (Rs) input and an unknown (Rx) input for measuring the ratio of the two resistors. All resistor connections are made using 4-terminal connections. Calibration verification can be made by performing an interchange measurement at any ratio. The interchange technique works at all ratios.


Measurements International’s 6242D-SW Windows®-based operating software features measurements automation, report generation, historical analysis, and tracking and correcting for resistor drift rates.

When you combine the 6242D with an MI IEEE-controlled 9400 Standard Resistor Oil Bath or 9300A Air Bath, you can automatically perform alpha and beta calculations on resistors under test.

You can export all data directly to Excel® for various test patterns or mainframe applications. Resistor baths (oil or air), instrument controllers, printers, system software, IEEE-488 interface, installation, and training are available for complete system packages.

When you use the 6242D in conjunction with our 6011 series of Range Extenders and 6150A Power Supplies, you can extend its range. Our Range Extenders include the 6011D/150 A and 6011D/300 A modules. The range can be extended further to 1 μΩ with our model 6013M/400 A Range Extender, model 6012M/2000 A Range Extender, or model 6014M/3000 A Range Extender.

Rx Resistance Value
Ratio Specification 6242D/6242D Options
1 Ω 0.1 Ω to 1 Ω 1 Ω 10 Ω 100 Ω
0.2 ppm 0.1/0.03 ppm 0.1/0.05 ppm 0.2 ppm
10 Ω 1 Ω to 10 Ω 10 Ω 100 Ω 1000 Ω
0.1 ppm 0.1/0.03 ppm 0.1/0.05 ppm 0.2 ppm
100 Ω 10 Ω to 100 Ω 100 Ω 1 kΩ 10 kΩ
0.1 ppm 0.1/0.03 ppm 0.1/0.05 ppm 0.3 ppm
1 kΩ 100 Ω to 1 kΩ 1 kΩ 10 kΩ 100 kΩ
0.1 ppm 0.1/0.05 ppm 0.1/0.05 ppm 0.8 ppm
10 kΩ 1 kΩ to 10 kΩ 10 kΩ 100 kΩ 1 MΩ
0.1 ppm 0.1 ppm 0.2 ppm 2.5 ppm
100 kΩ 10 kΩ to 100 kΩ 100 kΩ 1 MΩ 10 MΩ
0.25 ppm 0.5 ppm 0.3 ppm 5 ppm
1 MΩ 100 kΩ to 1 MΩ 1 MΩ 10 MΩ 100 MΩ
1 ppm 1 ppm 2 ppm 10 ppm
10 MΩ 1 MΩ to 10 MΩ 10 MΩ 100 MΩ
3 ppm 2 ppm 7 ppm
100 MΩ 10 MΩ to 100 MΩ 100 MΩ 1 GΩ
7 ppm 10 ppm 25 ppm

General Specifications

Resistance Ratio Range 0.001:1, 0.01:1, 1:1, 10:1, 100:1
Linearity ± 0.01 ppm
Resolution ± 0.001 ppm of full-scale
Input Channels 2 (expandable to 40 with 4220A Matrix Scanner)
Configuration 4-Terminal
Test Current Range 1 μA to 150 mA
Extended Test Current Option 150 mA to 3000 A
Test Voltage Range 1 V to 1 kV
Current Reversal 4 to 1000 Seconds
Time to Stated Accuracy (warm-up) < 1 minute
Temperature Coefficient ± 0.01 ppm/°C
Mode of Operation Front Panel Control or Automatic (IEEE-488)
Operating Environment 15 – 34 °C, 10 to 90 % RH non-condensing
Warranty 2 Year Parts & Labour

Information Request

  • Please fill in the details below to receive more information on this product

    * = Required Fields