Electrostatic Products

Monroe Isoprobe279L

Non-Contacting Electrostatic Voltmeter for Measuring Surface Potential

Advanced Energy’s Monroe Isoprobe 279L electrostatic voltmeter input range is limited to ±300 volts. The range limit improves the voltage resolution and noise performance and optimizes arc safety for sensitive measurements.

  • Range: ±300 volts
  • Accuracy: 0.1% or 10 mV, whichever is greater
  • Meter Resolution: 100 mV (four-digit LED)
  • Overview
  • Technical Specs
  • Service & Support
  • Distributors


The Monroe Isoprobe® 279L is based on the Isoprobe 279. It has an input range limited to ±300 volts (instead of ±3 kV) and uses an alternative high voltage power supply and amplifier section. The instrument features improved noise characteristics and meter resolution. The Isoprobe 279L is particularly useful in areas of electrostatic discharge monitoring and control. Typical applications include disk media research, bioelectric field studies, and contact potential measurements. 



  • Measure electrostatic surface potential without contacting the surface
  • Take advantage of the full range of Monroe 1034 probes with a restricted voltage range
  • Leverage improved noise characteristics and meter resolution with a limited input range of ±300 volts


  • Input range limited to ±300 volts (instead of ±3kV)
  • Lower measurement range optimizes arc safety for sensitive measurements
  • Improved noise characteristics and resolution with the limited input range
  • Performance

    Measurement Range

    To ±300 V

    Speed of Response

    3 ms, 10 to 90%, achievable at probe to surface spacing uo to 0.1 in with low-resolution probe


    100:1, ±3 V full-scale


    Less than 10 mV/h


    90 mV rms referred to input, typical

  • Mechanical

    Power Requirement

    100, 115, 230 VAC, ±10%, 50 / 60 Hz, 15 W

    Meter Resolution

    100 mV (4-digit LED)

    H x W x D

    1.7 x 8.2 x 15.1 in (44 x 208 x 384 mm),
    1.75 in rack mounting available (1 or 2 per rack)


    4 lb (1.8 kg)

    Probe Dimensions

    .35 x .35 x 2.85 in (9 x 9 x 73 mm)

    Probe Cable Length

    10 ft (3 m)

  • Typical Applications

    • Disk Media Research
    • IC Manufacturing and Handling
    • Contact Potential Measurements
    • Radiation Effects on Insulators and Semiconductors
    • Bioelectric Field Studies

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Product Support

Inside the U.S.: 1.800.446.9167 (option 2)
Outside the U.S.

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