The BI-870—A Dielectric Constant Meter from Brookhaven Instruments

The BI-870 Dielectric Constant Meter from Brookhaven Instruments allows users to easily measure dielectric constants.

Users can simply insert the probe in the liquid to be quantified, modify the two controls on the front panel and can read the dielectric constant from the display. The BI-870 Dielectric Constant Meter can precisely quantify in low- and high-dielectric solvents, such as solutions and mixed liquids.

Measurement of Dielectric Constants has Never Been so Easy with the BI-870

The BI-870 Dielectric Constant Meter features two selectable sensitivity ranges—1 to 20 and 1 to 200. Absolute precision is ±2%, while linearity and repeatability precision is better than 0.2%. The measurement signal used on the external cylinder of the probe is a low-distortion sine wave at a frequency of 10 kHz.

The amplitude is around 7 V rms on the 1–20 range and 0.7 V on the 1–200 range. The crystal-controlled frequency remains stable to around 1 part in 105. Users can determine the dielectric constant of the liquid sample by quantifying the current between the inner and outer cylinders of the probe.

Thanks to a stable voltage source and accurately known probe parameters, the dielectric constant can be displayed directly. Calibration is made easy by adjusting the back panel with a liquid of familiar dielectric constant.

The probe includes an open structure and can be cleaned easily. It is built from a pair of precision cylinders, machined from 316 stainless steel. A total of six Teflon balls ensure the cylinder spacing.

In case the probe is mainly used with low-dielectric constant hydrocarbon fluids, Brookhaven Instruments suggests cleaning by agitation in ethyl alcohol or acetone and then by mild drying with clean compressed air.

The probe should be cleaned before any residue dries on the cylinders. As the probe is made of Teflon® and stainless steel, it can be cleaned in nearly any solvent.

Features at a Glance

  • Compact size
  • Absolute precision to ±2%
  • Quick and user-friendly
  • Easy to clean, reliable, and rugged
  • Medium and high sensitivity ranges

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