ETS-Lindgren HI-3638 ELV/VLF Electric Field Meter - Manual (Page 24)

24 Application www.ets-lindgren.com
The HI-3638 uses this principle to detect electric fields by measuring the
displacement current caused by the ambient field between two closely spaced
circular disks. By placing such a detector in a known electric field, the
displacement current can be related directly to the magnitude of the field causing
it, permitting calibration. A circular sensing plate surrounded by a guard ring is
used in the HI-3638 and the displacement current developed between this
100 mm diameter disk and a closely spaced 300 mm circular disk electrode is
sensed and converted to equivalent electric field strength. Because the larger
electrode is used as a reference in the measurement process, for accurate
measurements of electric fields the sensor must be oriented perpendicular to the
incident field lines for maximum readings.