Measuring the effect of electromagnetic field EMF on any organism requires an accurate assessment of EMF exposure. EMF exposure is the measure of the strength of the electric or magnetic field present around the organism under study.
The cheap and easy availability of electricity during the 20th century has spread electric lines inside our homes to provide power for indoor lighting, cooling and heating systems, and other domestic appliances. Those power lines not only provide electricity but also generate EMF.
Can you avoid EMFs?
Any device that operates on electricity can develop an electric and magnetic field all around itself. One can easily avoid that EMF by moving away from the source as EMF strength decreases with an increase in distance.
Other non conductive objects can also help to avoid the EMF.
Moving away from one EMF source can result in moving toward another source. Moving closer to another source of EMF will expose you to a higher strength of EMF.
So now it’s impossible to find an area where there is no EMF. 4G and 5G enabled devices it’s impossible to avoid a high-strength EMF source.
Measuring EMF: The Basic
Electromagnetic field EMF is an invisible region of the electric and magnetic field that develops due to the flow of electric current through any conductor. EMF is divided into the following types
- Electric field
- Magnetic field
- Radiation (e.g. radio, Wi-Fi, and 4G network waves)
Criteria to Measure EMF
Studying the impact of EMF exposure involves the study of EMF source frequency and the strength of the field developed due to it.
EMF Frequency defines the type and nature of the EMF source. High-frequency EMF sources are far less dangerous as compared to low-frequency EMF sources.
When measuring EMF, we are mainly concerned about measuring the strength of EMF. The strength of EMF depends on the type of EMF radiation and the distance between the source and observer.
Unit of measure of Electric field
Electric field developed due to the flow of current through a conductor is identified in hertz (Hz). It’s always the frequency of the electric field source that we are concerned with. Depending on your contrary standard selection, your home either receives 50 Hz or 60 Hz.
Unit of measure of Magnetic field
Magnetic field develops due to the flow of current through metal is measured in Gauss or Tesla. As even a weak magnetic field from an EMF source can be dangerous so units of measure used for a magnetic field are milliGauss or milliTesla
Unit of measure of EMF radiation
EMF radiation (radio waves, Wi-Fi singles, cell phones signals, 3G, 4G, and 5G signals) has both electric and magnetic fields associated with it.
For the electric portion of the EMF radiation, the unit of measure volts per meter (V/m) is used and for the magnetic portion of EMF radiation; the unit of measure is Amp per meter (A/m).
To measure the EMF radiation both the electrical and magnetic part of the radiation is considered and the unit of measure watt per meter (W/m) is used.
Tools to measure EMF
An electromagnetic field is generated by alternating current or direct current. So they can be measured using the related meter. EMF meter can be used to measure the EMF generated by AC and Gaussmeter or magnetometer can be used to measure the EMF generated by DC.
EMF meters are very simple devices and can be used without any requirement of technical knowledge. It’s a non-contact device and can be used from a distance to accurately measure the EMF from a source like electric wire or EMF present at any area of your house.
How to Use EMF Meter
Steps to measure EMF using an EMF meter are
- Take an EMF meter
- Hold it at an arm length
- Point its front end toward the source of EMF or the required area
- Hold is steady for a few second
- Meter will show EMF reading instantly
- Repeat process to take 2 to 3 reading for the same scenario
- Average of all readings will be the value of EMF
To accurately measure the EMF value using an EMF meter, several values have to be taken from different positions and angles as EMF intensity can be different when measured from different directions.
Gauss meters are used to measure the strength of the EMF source developed by a DC. Like the EMF meter, it’s also a non-contact device but its operator has to go near the EMF source to measure the EMF intensity.
This is due to its working method; it has a probe that should be next few cm away from the EMF source for a few seconds to take an accurate reading.
How to Use Gaussmeter
Steps to measure EMF using Gaussmeter are
- Take a Gaussmeter
- Hold is probe toward the source
- Probe has to be near the source for accurate reading
- Hold the probe for a few seconds for an accurate reading
- Take multiple readings
- The average of the reading will be the EMF value from the DC
To accurately measure the EMF value using Gaussmeter, several values have to be taken from different points of the source as EMF intensity can be different depending on the design, geometry, and working of the source.
Tools to measure the magnetic field
Magnetic field developed by an electric current can be measured using two basic types of instruments, Search Coil, and Hall Effect sensor. From them, the search coil is the most used instrument for measuring EMF.
The search coil is a large device as compared to the EMF meter or Gaussmeter. It has a bar-like probe that has coils winded at one end.
How to use Search Coil
- The probe is inserted into the magnetic field area or place near a magnetic.
- After a few seconds, the probe is moved quickly away from the field.
- A computer system attached to the coil is used to record the reading of the magnetic field.
Hall Effect Sensor
Hall Effect sensor is a very simple, easy-to-use, and non-contact device. It is usually installed on machines where a change in a magnetic field is needed to be recorded. Its small sensor is attached to the machine computer or control panel to record readings.
It’s not usually used to measure EMF directly but it does measure EMF or magnetic field in different instruments like GPS, automobiles, and many other IoT things.
Fig: Hall Effect Sensor (image by How To Mechatronics, )
Tools to measure Electric field
There is a long list of devices that can be used to measure the electric field. An Ammeter can be used to measure the electric field in the form of an electric current.
The current clamp can measure the current in an electric circuit with any physical connection. A multimeter can be used to measure the voltage, current, and resistance in an electric circuit.
The current Clamp is small, compact, and easy to use. It’s a non-contact device that is used to measure both AC and DC. The current clamp can be set to measure current at different levels or ranges and it usually starts with measuring from maximum range down to the actual range of the EMF source.
How to Use a Current Clamp
- Steps of measuring the electric current using current clamp are
- Set the clamp for Ac or DC as per your requirement
- Set the clamp for the current range you want to measure and if the range is unknown then set the clamp to maximum level.
- Take the EMF source like an electric wire and place it in between the clamp of the current clamp
- Meter will show a reading of current instantly.
- There is no need to repeat the reading
A multimeter is a versatile device that can be used to measure the current, voltage, and resistance of an electric circuit. It’s a contact device where the user has to insert the probes of the meter into the circuit to measure the values.
The multimeter has a predefined setting to measure current, voltage, and resistance with each set having its range under which it can measure accurately.
How to Use Multimeter
Steps of measuring the value of electric field are
Set the meter as per your requirement that is inserting the probes into designated ports of the meter and direct the dial toward the property which you are going to measure.
Select the range for which you are going to take the measurement
- Start the meter
- To measure the voltage, place probes of meter parallel to the source of resistance
- To measure the current place is probes in series with the electric circuit
- To measure resistance place probes in parallel to that particular resistance
- Meter will show accurate reading instantly
- There is no need to repeat the process
With the development of smart electrical devices like cell phones, laptops, and other electrically controlled home appliances and the complete dependence of humans on these smart devices for daily tasks, the probability of continuous EMF exposure is higher than ever.
If an organism is exposed to EMF for an extended period, it can have some negative biological effects. Studying the impact of EMF exposure involves the study of EMF source frequency and the strength of the field developed due to it.
Frequency is measured in Hertz and strength is measured in Watts. The tools like EMF meter and Gaussmeter that can be used to measure EMF value without the requirement of any technical knowledge.
- Electromagnetic Field (EMF) Meter PCE-EMF 823 by pce instruments at [https://www.pce-instruments.com/english/measuring-instruments/test-meters/electromagnetic-field-meter-pce-instruments-electromagnetic-field-emf-meter-pce-emf-823-det_5854132.htm]
- HT Digital Gaussmeter With Peak Hold – Can Display Gauss or Tesla by a pex magnet at [https://www.apexmagnets.com/magnets/accessories/ht-digital-gaussmeter-with-peak-hold-can-display-gauss-or-tesla]
- Video: Search Coil Experiment (measure magnetic field strength) by A Level Physics HQ at youtube [https://www.youtube.com/watch?v=vb8KwB0ANrg]
- Video: What is Hall Effect and How Hall Effect Sensors Work by How To Mechatronics at youtube [https://www.youtube.com/watch?v=wpAA3qeOYiI]