The AC Magnetic Mode uses three ferrite-core coils, pointing in the X, Y, and Z directions, located
near the top of the meter. The X, Y and Z signals are combined into a true magnitude of the
eld strength, independent of which direction the meter is pointed. Maximum range is 100.0
mG, with resolution of 0.1 mG, and accuracy of ±4% of reading at 50 Hz and 60 Hz. A frequency
response graph of Standard and Weighted modes is on page 7.
In most homes or oces, some areas are “hot” spots with high readings. Most often, this is
caused by magnetic elds, which come largely from unpaired internal wiring. Contrary to
popular belief, power transmission lines and transformers do not generally contribute as
much magnetic eld indoors as does internal wiring. This is because high voltage lines carry
relatively low current, and transformers are shielded. Other magnetic sources include video
displays, uorescent lights, light dimmers, transformers that are inside consumer devices,
electric blankets, heaters, and anything with a motor. Much of the total eld strength is from
frequencies that are harmonics or multiples of 60 Hz (120 Hz, 180 Hz, etc.). Cars (especially near
the front oorboard) and motorcycles have fairly strong elds at frequencies higher than 60 Hz.
AC Electric Field Detection
To measure the eect of an AC electric eld on the human body, turn the knob to the Weighted
ELEC setting and hold the meter at the location to be measured. For standard technical AC
electric eld measurement, turn the knob to the Standard ELEC setting.
Your body can easily shield electric elds; the reading is lower if you cover the top surface of the
meter with your hand. Also, the presence of your hand at the back of the meter compresses the
electric eld, making it read somewhat higher than if the meter were suspended from a string
or held on a board, away from you. In either case, the true electric eld near the meter will be
displayed.
The AC Electric Mode uses a metal plate sensor under the top of the meter. Circuitry similar to
the magnetic section converts the signals into an electric eld strength. Maximum range is 1000
V/m with resolution of 1 V/m and accuracy of ±5% of reading at 50 Hz and 60 Hz. A frequency
response graph of Standard and Weighted modes is on page 7.
A few areas in most homes read high on the electric eld setting. These include areas near
improperly grounded equipment, the front of video displays, and uorescent lights.
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