To measure AC Magnetic Fields (what some people mean when they say "EMF"), from powerlines, wiring, lighting and appliances we use a gaussmeter. Gauss meters measure the strength of the magnetic field at the location of the meter. Because magnetic fields are oriented in space, the position of the meter will affect the reading (see discussion of 1 axis vs. 3-axis meters). Gaussmeters, also called Teslameters, can also be used to locate the source of a field, and to measure the performance of magnetic shielding.
The main features to consider when choosing a gauss meter are:
- Readout type: lights, sound, numbers, needle gauge
- Range: how sensitive on the low end, and the upper limit on the high end
- Axis: 1-axis only, 3-axis only, switchable 1-axis and 3-axis
- Accuracy: While high accuracy is desirable, it is not often necessary for locating "hot spots".
- Outputs: voltage output or PC interface for data logging
- Frequency weighting: see the short video on frequency weighting.
More Great Choices... Click below to order or more information
This little meter measures the level of ELF magnetic field radiation from power lines, computers, kitchen appliances, and more! The easy to read scale, unique built-in audio signal and auto shut-off make it simple to use and a great way to find hidden sources of ELF frequency magnetic fields.
Most experts agree that chronic exposure to more than 2.5 milli-Gauss is inadvisable. This meter will show you which areas are above or below 2.5 milli-Gauss in the 50 - 60 Hz frequency range.
Hand-held, lightweight and durable, with two easy to read scales (0-1 mG, & 0-10 mG), and dramatic audio signal. Our favorite meter for demonstrating the presence of dangerous EMFs to others and paranormal work. Requires one 9V battery (not included). Calibrated at 50-60 Hz.
Axis
Range
Resolution
Frequency
Accuracy
1
0-1 mG 0-10 mG
0.1 mG 1 mG
50/60+ Hz
no spec
What is unique about this meter? Lightning fast needle response, audio function
Includes nice instructions on how to perform a proper survey of your home, office, or school yard.
"I tested it on several items and was surprised how much some things registered. My electric blanket registered extremely high so now I will warm up the bed and turn it off once I go to bed. My clock radio that's about a foot from my head was so high I unplugged it."
True-RMS 3 Axis AC Gaussmeter with all the features you could want. A real technological breakthrough.
Axis
Range
Resolution
Frequency
Accuracy
3
0-250 mG 0-25.0 microT
0.01 mG 0.1 microT
15-5500 Hz
±½dB 30 to 5000 Hz
What is unique about this meter? Backlit, peak/hold function, toggle mG/microT, toggle all axes
Flat frequency response:
±½dB 30 to 5000 Hz
-3dB 15 to 5500 Hz
Selectable axis (3D, X, Y, Z) on ALL features
Peak Axis (which axis has the strongest field)
On-Screen Graphing (Horizontal bargraph of field strength)
Max Hold
Variable Brightness Blue LED Backlight
Selectable units: milliGauss or microTesla
Fast Update Rate: 2.5 times per second
Low battery indicator
Alkaline battery (included) typically lasts ~15 hours at default backlight setting. Suitable for general purpose magnetic field readings, and great for paranormal work as well. Lowest price for a 3 axis digital gaussmeter! 1 year wty. Made in USA.
Compact and easy to use, this digital unit can measure ELF (13 Hz to 1 kHz) and/or VLF (1 to 75 kHz) magnetic fields in either single axis mode (to help identify the orientation of the field) or 3-axis mode (which makes routine measurements much faster and more reliable). Range from 0.01 mG to 1999 mG. 5½digit display. 3% accuracy from 45 to 5000 Hz but useful from 13 Hz to 75 kHz. Very simple: One knob selects from these 3 modes: 3-axis ELF+VLF, 3-axis VLF, 1-axis ELF+VLF. Uses standard 9V battery (included). Made in USA. One year mfr warranty.
Axis
Range
Resolution
Frequency
Accuracy
1 or 3
0-1999 mG
0.01 mG
13-75k Hz
3% from 45 to 5000 Hz
What is unique about this meter? Distinguish ELF from VLF signals, wide frequency range
In paranormal research, the presence of man-made 50 or 60 Hz EMF signals can give rise to "false" readings. Wouldn't it be great if you could set your EMF meter to ignore these ever-present signals and just pick up everything else? Now you can! With this meter you can look at just the 50/60 Hz signal, or just the harmonics, or just everything else. And you can compare that reading to the overall reading on the same screen at the same time! Adjustable back light too, because it was designed with paranormal research in mind.
Also perfect as an all purpose True-RMS 3-Axis meter with high sensitivity. Great for distinguishing a 50 or 60 Hz signal from the higher frequency harmonic signals which often accompany power line magnetic fields.
Axis
Range
Resolution
Frequency
Accuracy
1 or 3
0-250 mG
0.01 mG
15-5500 Hz
±½dB 30 to 300 Hz
What is unique about this meter? 3-axis Backlit, peak/hold function, toggle mG/microT, toggle all axes
More Features:
Flat frequency response:
±½dB 30 to 300 Hz
Selectable axis (3D, X, Y, Z) on ALL features
Two display styles:
On-Screen Graph: select any of 3 values: total RMS, notched, bandpassed
Digital readout: RMS broadband plus select:
60Hz only, or 60Hz+Harmonics, or 50Hz, or 50Hz+Harmonics
Variable Brightness Blue LED Backlight
Max Hold of any of the 3 values
Selectable units: milliGauss or microTesla
Low battery indicator
Alkaline battery (included) typically lasts ~20 hours at default backlight setting. Feature rich and easy to use, same meter works for both 50 or 60 Hz. Great price too! 1 year wty. Made in USA.
This FWBELL 4180 model features three axis sensors which insure that measurements remain accurate regardless of the orientation of the instrument.
Lightweight and self-contained, this unit is ideal for commercial and home use. This model accurately measures Extremely Low Frequency magnetic fields (ELF) generated by electrical equipment. Applications include detecting magnetic field emissions from a wide variety of sources, including video display terminals (VDTs), AC power lines, office equipment, household appliances, and all types of electric and electronic equipment. Includes certificate of calibration, soft carrying case, four AAA batteries and 90 day warranty.
Calibration Frequency 50/60 Hz
Low Cost, Small Lightweight(6.3 Oz) and Portable(4"x2.6"x1")
High Accuracy(2% error) with BW: 40-600 Hz
MilliGauss or MicroTesla Display Options
Range 0.1 mG to 511 mG with 0.1 mG resolution
4 AAA alkaline batteries & 50 hours life
Selectable X. Y, or Z Axis plus Vector Summation
True RMS Reading w/ 3 1/2 digit LCD
Made in the U.S.A.
Includes batteries, calibration certificate, and carrying case!
FW Bell 4180 (Refurbished) Cat. #A90999 ... Reg. $425.00
A useful and reasonably priced meter for measuring both AC and DC magnetic fields. Easy to use with external single axis probe. Excellent range with great features including:
DC and AC (40 Hz to 10 KHz) magnetic field measurement
High sensitivity: down to 0.1 mG
High range: up to 3000 mG
Accuracy: ±(2% + 2 mG)
N pole/S pole indicator
Reads in mG or µT (toggle)
Zero adjustment button (tare) for relative measurement
Data hold function for freezing the current value on display
Records Maximum and Minimum readings with Recall
1 second sampling time
3.5 mm data output jack
What is unique about this meter? Measures both AC and DC magnetic fields
Uses 6 AAA batteries (not included). Can also be power by external DC 9V adapter (sold separately).
A practical guide for reducing AC magnetic fields produced by building wiring and improper grounding practices. Step by step instructions for detecting wiring problems and a full description of common wiring errors and how to correct them. This guide is for anyone who wants to inspect their own home, electricians and electrical inspectors, those starting a new profession in EMF consulting, as well as those involved with the process of building construction such as architects and contractors. Utility personnel involved in EMF measurements can profit from this information. Completely updated in 2012.
TRACING EMFs DVD (Cat. # A531-DVD)....................$19.95
Typical Applications include checking the 50 and 60 Hz magnetic fields produced by such equipment as transmission lines, computers, electric blankets, electric appliances, televisions, etc. Very high accuracy and sensitivity. Made in USA by INTEGRITY DESIGN.
Specifications:
Portable, digital readout
Auditory and visual Alarm
Remarkable Linearity
Narrow Bandpass Filter
Sturdy Shielded and Grounded Probe
200 mV recorder Output
Range Settings: 2, 20, 200, 2000 milliGauss
Bandwidth: 11 hertz at 3db
Battery life: at least 48 hours with one 9v alkaline battery included
Weight: 15 oz. (425 grams)
Sensor: External Air coil type with 8" handle
Very high accuracy: 1% maximum error based on EPA report
What this meter lacks in resolution it makes up with ease of use and very low cost. Will measure ELF/VLF magnetic fields in the frequency range of 20 - 10,000 Hz, with a minimum sensitivity of .25 mG. Laboratory tested and documented for accuracy.
Three LED lights signal field strength:
0 - 2.5 mG ("safe")
2.5 - 7 mG ("caution")
8 or more mG ("danger")
Axis
Range
Resolution
Frequency Response
Accuracy
1
0.25 to 8+ mG
1 of 3 LEDs
20 to 10k Hz
no spec
What is unique about this meter? Lowest cost gaussmeter available
Single axis sensor, on/off toggle switch. One fresh 9V battery required. Useful for preliminary surveys of home, car, or office. Very popular for paranormal work too!
Common ELF magnetic field frequencies are within the range of human hearing. This simple set up converts the AC magnetic signal directly into a dramatic corresponding sound signal. A 60 Hz powerline field sounds like a 60 Hz hum (a low note on piano keyboard). Harmonics can easily be heard, as well as clicks, static, and hash. LED displays are especially noisy. The strength of the field is proportional to loudness.
Unit includes a single axis probe on 2 foot cable and audio amplifier. You can even use an optional earphone/headset for discreet operation. Use it to "sniff out" sources of interference, offending EMF, check shielding designs. Makes a great educational tool. Requires one 9V battery.
Equipment Set-Up for Analyzing Frequencies from 0-60 Hz
Analyzing frequency information from ultra-low frequency magnetic fields can be extremely challenging. Air coil type magnetic field probes just don't have the necessary sensitivity below about 20 Hz.
The voltage output from our Geomagnetometer (read more) provides excellent frequency information from low frequency signals. The amplified, unrectified, Hall effect probe output retains all the frequency information from the magnetic field under investigation.
Simply connect the voltage output (3.5mm mono jack) from the Geomagnetometer to the oscilloscope or spectrum analyzer and monitor both field strength AND waveform, frequency, and spectrum distribution of your signals. Because the Geomagnetometer output produces 200 mV at full scale, you get plenty of signal to the oscilloscope or spectrum analyzer.
For example, on the 0-2 mG range: 2 mG produces 200 mV output, .05 mG produces 5 mV. On the 0-200 mG range: 200 mG produces 200 mV output, 5 mG produces 5 mV.
In our tests, the actual output range from the Geomagnetomer extends significantly beyond 200 mV, and was useful up to 60 Hz and beyond. Interested in .01 Hz? 2 Hz? 7.8 Hz? No problem! You can analyze fluctuations in the Earth's magnetic field, fields from audio recordings, and almost any other ultra-low frequency magnetic field source. Possibly biologic and paranormal sources?
Connect your computer to this meter's output to make a spectrum analyzer (with optional PC Based Oscilloscope)! You can even add the Audio Amplifier to boost weak signals.
Individual Components:
Geomagnetometer only (Cat. #A3100) ............................................ $750.00
To connect Geomagnetomer to your PC, you will need:
6 foot 3.5 to 3.5 mm mono plug cable only (Cat. #A134-cable) ......... $4.95
Zero Gauss Chamber
This chamber can be used with the Geomagnetometer to provide a zero gauss (magnetic field-free environment) reference, enabling you to take absolute readings of the ambient magnetic field (the Earth's magnetic field is typically around 500 mG). Concentric welded 12" long tubes (1" ID chamber) with stand, made of high permeability magnetic shielding alloy provide excellent shielding.
Zero Gauss Chamber (Cat. #A3105) ......... $395.00
9V alkaline battery included & DC adaptor, Hard case is included
Two year parts and labor warranty, made in USA
Typical Applications include checking the frequencies and magnetic fields produced by such equipment as computer monitors, television sets, power lines, induction heaters, industrial, scientific and medical equipment and electric appliances, etc.
Truly unique. You get 3-axis VLF readout with simultaneous frequency indication (1-200 kHz), peak hold, alarm, datalogging, and RS-232 connection. Wow! Portable and easy to use. Covers 0.2 - 2000 mG in 2 ranges.
Typical applications include checking the frequencies and magnetic fields produced by such equipment as computer monitors, television sets, video display terminals, induction heaters, industrial, scientific and medical equipment and ground wave energy network. Hard case, 9V alkaline battery & DC adaptor included. Two year parts and labor warranty. Made in the USA
Qi Wireless Charging
Qi wireless charging uses inductive power transfer in the 110-205 kHz range. This frequency is emitted from the charging station and can be detected in its vicinity. This VLF 3-axis Gaussmeter is an excellent choice for measuring this emission.
Specifications:
Frequency response: 1-200 kHz
Analog output for X, Y and Z axis waveform
Predominant frequency indicator for each channel
Isotropic sensor... Switchable to single axis mode
True RMS measurement with peak hold
Error ±3% maximum
16 character x 2 line display
Sensor: External three Axis X, Y, Z Air coils type with 8" handle
Sensor dimensions: 1.9" diameter, 3.3" length
Datalogging up to 32,000 data points, adjustable interval
Datalogging interval adjustable from 1 ms to 9999 s (software not included)
Record data of all channels to PC via RS-232 communication port
So what magnetic fields do you want to measaure? AC? DC? Need frequency information too? This meter does all that and more. Simlutaneous digital readout of field strength and predominate frequency, true RMS measurement with peak hold, One volt full scale analog voltage output, alarm, dataloging up to 32,000 data points, and 3 % error guarantee. External probe.
Operate in 1 of 3 modes:
3 Ranges:
DC only
300 G (100 mG resolution)
AC only: 20 Hz - 1 kHz
3 kG (1 G resolution)
AC + DC: 0 - 1 kHz
30 kG (10 G resolution)
Completely portable. 4 AA alkaline batteries included and optional 6V DC adaptor available. Choose axial probe, transverse probe, or both. Zero gauss chamber (included ) helps when zero-ing the unit.
This chamber can be used with the DC/AC Gaussmeter to provide a zero gauss (magnetic field-free environment) reference, enabling you to take absolute readings of the ambient magnetic field (the Earth's magnetic field is typically around 500 mG). Concentric welded 12" long tubes (1" ID chamber) with stand, made of high permeability magnetic shielding alloy provide excellent shielding.
Zero Gauss Chamber (Cat. #A3105) ......... $395.00
Perfect for meters, instruments or cameras. Fits plenty of stuff in a compact space. This rugged case features aluminum trim, riveted corners, lock and keys, carry handle and metal hinges. Black hard sidewalls. Black padded inside walls but no foam. Outside: 12'' x 10'' x 4''; Inside: 11" x 9¼" x 3¼".
You can also use it to store:
important papers
seeds
toiletries
knitting / sewing supplies
crayons / chalk
photos
coupons
medicines / vitamins / homeopathy
hand gun / ammo
tools
collectibles
art / craft supplies
cash / valuables
diary
love letters
small toys, Legos, puzzles
business cards
lunch
receipts
baseball cards
Deluxe Instrument Case (Cat. #A711) .............................................. $19.95
Run your meter on household power for continuous measuring
Want your meter to take continuous measurements all day? The answer is here. This 9v Battery Terminal Adapter plugs into any North American wall outlet and connects directly to the locking battery terminal on ANY 9-volt device. Only works with locking 9v battery terminals (see image).
What is the real difference between a single axis and a triple axis gaussmeter?
Because magnetic fields are oriented in space, a sensor will only detect the field properly if it is aligned with the field. A single axis meter has only one sensor in it. Therefore to get a correct reading with this type of meter, you must slowly rotate the meter until you find the maximum reading. This will be the correct reading. If the meter is turned 90° from the maximum reading, it will read nearly zero. It is easy to understand how it is possible to get a lower than actual reading if the meter is not properly aligned.
A three axis meter has 3 sensors in it, all aligned at right angles to each other. Therefore, this type of meter is always correctly aligned and no rotation is required to get a correct reading. This type of meter takes less time to use but generally costs more that its single axis counterpart. See 3-Axis Digital Gaussmeter and Trifield Meter for examples of 3-axis gaussmeters.
See lots more information on our FAQ page. (Frequently Asked Questions)
Can't decide which meter is right for you? Click for a handy Meter Selection Guide to learn how to choose a meter to measure EMF
3-Axis Backlight Gaussmeter (Cat. #A107) ... $269.00 
3rd edition, by Karl Riley.
Very High Accuracy and Sensitivity
Common ELF magnetic field frequencies are within the range of human hearing. This simple set up converts the AC magnetic signal directly into a dramatic corresponding sound signal. A 60 Hz powerline field sounds like a 60 Hz hum (a low note on piano keyboard). Harmonics can easily be heard, as well as clicks, static, and hash. LED displays are especially noisy. The strength of the field is proportional to loudness.
Analyzing frequency information from ultra-low frequency magnetic fields can be extremely challenging. Air coil type magnetic field probes just don't have the necessary sensitivity below about 20 Hz.
This chamber can be used with the Geomagnetometer to provide a zero gauss (magnetic field-free environment) reference, enabling you to take absolute readings of the ambient magnetic field (the Earth's magnetic field is typically around 500 mG). Concentric welded 12" long tubes (1" ID chamber) with stand, made of high permeability magnetic shielding alloy provide excellent shielding.
