ETS-Lindgren HI-3604, User Manual

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Waveform Measurements
A useful feature of the HI-3604 is the ability to display waveform information
about electric or magnetic fields being sensed. The waveform display output is a
1/8 inch phone jack located on the bottom of the instrument case. Using this
output, the waveforms of the incident fields maybe monitored by connection to an
oscilloscope. The oscilloscope connects to the analog output jack on the HI-
3604.
Figure 4-4 is an oscilloscope photograph of the magnetic field associated with a
common incandescent light bulb. The field waveform is seen to be essentially a
pure 60-Hz sinusoid.
Figure 4-4: Waveform of Incandescent Light Bulb
Figure 4-5 is a picture of the waveform of the same light bulb magnetic field
except that a light dimmer has been introduced to the power supply to the light
bulb. In this case, the dimmer has been adjusted to approximately half brilliance
and the chopping action of the dimmer is clearly shown. Through a chopping of
the waveform, less power is delivered to the bulb resulting in a lower light level.
Figure 4-5 represents the waveform of the current supplied by the light dimmer.