Specifications

B-field Exposure From Induction Cooking Appliances 19
The measurement time interval is 250 ms. The rms-value, given in [µT], is continuously
integrated over four intervals, and the integration time of the rms calculation is fixed at 1 s. The
Narda ELT-400 probe can also operate as an active probe, using the three separate, analog signals
corresponding to the three spatial axes x, y, and z. Connecting it to an external oscilloscope or
spectrum analyzer allows temporal and spectral measurements.
In this project, the Narda probe ELT-400 is used in field strength mode, which is a measurement
of the magnetic flux density based on broadband evaluation of the signal, for the bandwidth
30 Hz to 400 kHz. The measurement uncertainty of the instrument is ±4 % (50 Hz to 120 kHz).
The frequency response for the selected bandwidth limits 30 Hz and 400 kHz is −3 dB ±1 dB.
The settings selected are given in Table 4. The intrinsic noise is 70 nT and 320 nT for the low
and high range settings, respectively.
Table 4: Settings of the Narda probe ELT-400.
Mode 320 µT
Range Low High
Overload Limit
a
32 µT 320 µT
Nominal Measurement Range
b
2 µT 20 µT
Intrinsic noise (rms) 70 nT 320 nT
a
Maximum measurable rms-value of a sine wave.
b
Maximum measurable rms-value of a signal of any shape
with a crest factor (peak value/rms-value) of less than 22.