ETS-Lindgren HI-3604 ELF Survey Meter - Manual (Page 15)

HI-3604 Manual Page -- 7
Figure 2-2
HI-3604
Electric Field Response
The HI-3604 Power Frequency Field Strength Meter package
includes the Readout-Sensor assembly, batteries, a fitted
carrying case and a user manual.
Instrument accuracy is derived from a field calibration using a
one meter diameter pair of Helmholtz coils for establishing an
accurately known magnetic field strength, and a pair of parallel
one-meter square aluminum plates separated by 30 cm for
creating a known electric field strength. In the case of the
Helmholtz coils, a precisely controlled and measured sinusoidal
current is driven through the coils and, based on the dimensions
of the coils, the magnetic field strength in units of milligauss
(mG) is calculated. For electric fields, a sinusoidal voltage
impressed across the two parallel plate electrodes is directly
measured and used to calculate the electric field strength by
dividing the applied voltage by the plate spacing to obtain field
strength in units of volts per meter (V/m). In each case, both
currents and voltages in the calibration set-ups are determined
with a true RMS detector.