What is an EMF Meter?

An EMF meter is a portable handheld measuring instrument used to measure electromagnetic radiation generated by electronic devices and electric installations in a surrounding environment. The EMF meter simultaneously measures and displays the electric field (50/60 Hz) radiation in V/m, magnetic field (50/60 Hz) radiation in mG/μT, and RF field strength (MHz to GHz) in μW/m²‐mW/m² or μW/cm² or mV/m‐V/m or mA/m or dBm in the surrounding environment of electronic devices & electric installations. It can measure the EMF from low-frequency ranges to the RF range. The EMF meters are available to measure both static/permanent magnet (DC) and alternating magnetic (AC) fields (EMFs). 

The EMF meters are ideal for measuring the radiation from the power lines, electrical appliances, household appliances, computers, high voltage cables, industrial devices, cell phones, base stations, and microwave leakage.

Excessive EM radiation can be harmful. Hence, these measurements from EMF meters can help manage the radiation power from various devices in a surrounding environment to ensure the public people/person health or RF technicians working in the vicinity of a base station (especially in front of the antennas).

The handheld EMF meter is equipped with a built-in electromagnetic radiation sensor (coil/antenna), amplifier, comparators, ADC, a micro-chip processor, LCD display, buzzer alarm &LED for providing accurate readings. The buzzer will sound or LED blink when the measured results exceed the safe value. 

What is an EMF Probe?

An EMF meter may use an external electromagnetic sensor called an EMF probe. An EMF probe consists of a sensor, a preamplifier, a transmission line, and a connector. The EMF probe can be thought of as an antenna (usually isotropic antenna) used to measure EMF radiation which is then connected to a spectrum analyzer or EMF meter (that uses an EMF probe as the external sensor).

EMF probe with a handheld spectrum analyzer to measure EMF

The EMF meters are available in single-axis and tri-axis categories. The single-axis EMF meter measures one dimension of the EMF at a time. Thus, a single-axis meter needs to be tilted and turned on all three axes to obtain the full measurement. A tri-axis EMF meter measures all three axes (X, Y, Z) simultaneously; hence EMF measurement can complete quickly.

Key features of EMF meter:

• Simultaneous measurement of multi-Field measurements: Magnetic Field, Electric Field, and Radio Frequency (RF) Strength.
• Both single-axis and trible-axes meters are available
• Facility to store the historical records
• Available with external electromagnetic sensor (EMF probe with low and high-frequency range)
• Displays the magnetic field measurement  in Gauss (mG) / Tesla(uT)
• Displays Electric field measurement in V/m
• Displays RF Strength measurement in (uW/m² ~mW/m²) (μW/cm²) (m V/m ~V/m) (mA/m) (dBm).
• Data hold and auto power-off functions
• Brightness control options (low, middle, high)
• Portable, lightweight, and easy to use.

How does an EMF meter work?

Simple EMF meter working schematic 

Usually, an EMF meter is equipped with a built-in electromagnetic sensor (coil/antenna) that converts the EMF in the surrounding environment into an electric signal (V). This electric signal is then amplified and converted into digital form by ADC. Now the LCD screen of the EMF meter shows the reading with the help of ADC and microprocessor. The measured readings are always compared with predefined safe limit values by the comparator circuits. If the measured reading exceeds the safe value, the buzzer will sound or LED blink. An EMF meter may use an external sensor (EMF probe) for measurement.

Specification details of EMF meter:

Magnetic fields (50/60 Hz) range: Represents the magnetic field range that can be measured by the EMF meter. The magnetic field is measured in Gauss/mG or Tesla/ μT.

 Electric fields (50/60 Hz) range: Represents the electric field range that can be measured by the EMF meter. The electric field is measured in V/m.

RF strength (MHz to GHz) range: Represents the frequency range and the RF field strength that can be measured by the EMF meter. It is measured in μW/m²‐mW/m² or μW/cm² or mV/m‐V/m or mA/m, or dBm. 

Resolution: Resolution represents the smallest change that can be measured by the EMF meter. In EMF meters, the resolution of the magnetic field is represented in Gauss/mG or Tesla/ μT, the resolution of the electric field is represented in V/m, and the resolution of RF strength is represented in μW/m²‐mW/m² or μW/cm² or mV/m‐V/m or mA/m, or dBm. 

Accuracy: Represents the measurement accuracy of the EMF meter. The accuracy of the EMF meter refers to the closeness of the measured reading to its true value. The EMF meter has a magnetic field and electric field accuracy represented in ± (X%+Y digit) and the RF strength accuracy in ± dB.

Dimension: Represents the dimension of the pre-amplifier in L x W x H mm.

Weight: Represents the weight of the pre-amplifier in Kg.

EMC Directory has listed EMF Meters and Probes from the leading manufacturers. Narrow down on EMF meters based on the configuration and various specifications. View product details, download datasheets and get quotes.