EMF Detector Circuit Working and Its Applications

In general, there are two types of currents with which the electromagnetic fields are created – direct current (DC) and alternating current (AC). The EMF meters measure the electromagnetic fields that are produced by AC. To create it more clearly, it’s the type of current that surges through electrical devices we use every day, such as the TV and microwave. The main feature of the alternating current that creates the electromagnetic field that the EMF measures are that this type of current moves in two directions up to sixty times in a minute, where the direct current is static and cannot be measured by most of the EMF models industrial workers use.

What is EMF Detector?

EMF detector is a test and measurement apparatus that is used in different industrial applications for detecting problems in electrical wiring and power lines. The EMF meter gives information about the workflow in the electromagnetic field by measuring electromagnetic radiation flux density (DC). Moreover, this instrument can track the changes in the electromagnetic field that occur over a confident period of time (AC fields).

Working Principle of EMF Detector

The EMF meters detect issues in the electromagnetic field by the measurable changes in the quantity of electric or magnetic energy that flows in the field that is being precise. This is complete with the highly-sensitive components which are part of the arrangement of this test and measurement device. According to the fluctuations in the quantity of electric or magnetic energy (if there are any), the EMF meter can specify existent issues in the work of the electrical wiring and power lines. This method bigger problems can be prevented and proper workflow in the manufacturing sites is ensured.

EMF Circuit Design

An electromagnetic field probe intended to identify changing electric and magnetic fields. The probe has a meter output and a headphone socket as well. This tester is designed to position stray electromagnetic (EM) fields. It will simply detect both audio and RF signals up to the frequencies of approximately 100 kHz. Note, however, that this circuit is NOT a metal detector, but will detect metal wiring if it conducts AC. The frequency response is from 50Hz to regarding 10 kHz gains being rolled off by the 150p capacitor, the gain of the op-amp and the input capacitance of the probe cable.

EMF Detector Circuit

Stereo headphones may be used to monitor audio frequencies at the socket, SK1. We used a radial type of an inductor with 50cm of screened cable threaded during a pen tube. The cable may be used with a plug and socket if preferred.

Emf Detector Circuit
Emf Detector Circuit

The output signal from the op-amp is an AC voltage at the frequency of the electromagnetic field. This voltage is additionally amplified by the BC109C transistor, before being full-wave rectified and fed to the meter circuit. The meter is a small dc panel meter with an FSD of 250uA. Rectification takes place via diodes, meter, and capacitor.



If you include access to an audio signal producer you can apply an audio signal to the windings of a little transformer. This will set up an electromagnetic field which will be simply detected by the probe. Without a signal generator, just place the probe near to a power supply, mains wiring or another electrical tool. There will be a deflection on the meter and sound in the headphones if the frequency is below 15 kHz.

Types of EMF Detector

EMF meters are available in two types:

  • Single Axis
  • Tri-Axis

Single Axis Meter

A “single-axis” or directional meter to measure the AC magnetic field strength in just one direction at a time. This strength-in-a-direction is known as the field’s “component” in that direction – regularly either perpendicular to the face of the meter, or along the length of the meter. To decide the field’s total strength (quite than just its strength in one direction) one regularly tip the meter to a variety of orientations, looking for an orientation that gives the utmost reading. This is not always explained very well in the meter’s directions, and it can be boring to do. Particularly if one is concurrently trying to find the location that gives the highest reading (near a supposed field source, say).

Single Axis Meter
Single Axis Meter

Furthermore, unless we build up some particular tricks, the tedium with a single-axis meter becomes even greater if the meter is digital -because comparing one set of digits with another set we saw a second earlier (as we shift or rotate the meter looking for a maximum) is essentially slower than watching whether a pointer goes up or down.

Thus, mistakes tend to get complete when using a single axis EMF meter. For occurrence, we may start by correctly influential the field’s orientation at an exacting place in a room (by rotating the meter to a higher reading there) but then we may try to move the meter approximately the room to find if there is a higher-field location, without remembering to do more checks on the field’s angle to create sure we’re still pointing it properly. Particularly if a field’s source is close by, the field angle may modify in a short distance. We may move the single-axis meter near this source but see the readings go down because we’re no longer holding the meter at the maximum-field orientation.

Tri-Axis Meter

All this can be a genuine pain. One solution is to spend approximately an extra hundred dollars (give or take) to buy a “three-axis” meter – a non-directional kind that takes three instantaneous single-axis readings in three equally perpendicular directions and then combines them electronically to give a “resultant” reading that is regularly the same field strength as we would get by rotating the meter to a higher reading. The only other good solution is to get the best, most-convenient single axis meter (i.e. One that responds speedily, but progressively and legibly when rotated) and then learn a bag of tricks that speed things up. For instance, in many situations, vertical or near-vertical is the majority likely field orientation.

Tri-axis EMF Meter
Tri-axis EMF Meter

Thus a helpful trick for using a single-axis meter is to start with the meter held to read a vertical field – and then tip it forward and back, and left and right, to see if our first deduction is correct, or if one more angle gives us more. That is not a bad technique, using a good single axis meter. The next significant trick is to use the prior information of the field angle we expect from an exacting source – possibly a power line that we see in the face of us, or a current-carrying water line that we know is below our feet – and let that give us our “first guess” as to the maximum-reading field direction.

But this is extra than now a way to get a fast reading. What this method also does for us is to tell us if our hypothesis is right concerning what is causing the fields we’re seeing. If the fields point in some other way, then there must be another source that we’ve missed – maybe a different current-carrying pipe or set of wires, and not the one we were looking at. With a three-axis meter, we don’t acquire that kind of actuality check; we now see imprecise areas of eminent fields. We may compose mistakes, trying to work without the full in order counting the field’s direction; and we may persevere in a wrong analysis, and misuse time that way.

It is quite an ordinary mistake in preparation for field mitigation that something also is causing the fields besides what seems palpable at first. We require help from each clue we can get, counting field direction. Intentionally throwing away that information makes things harder rather than easier. Of course, we have to know how to use the directional information once we get it, but it’s not that firm to learn.

Applications of EMF Detector

The applications of an EMF detector includes the following

  • The electromagnetic detector at applying in EMF Scanner
  • Entity sensor pro-EMF Detector
  • Ghost Hunter (EMF, EVP, SCAN)
  • Ultimate EMF detector
  • EMF Analyzer
  • EMF Strength Meters
  • Radio Frequencies
  • Televisions and Computer games

Thus, in the above article we are discussing the EMF detector, what are the EMF detector and working principles of EMF detector. The main theme of the article is how to design the EMF detector circuit, types of EMF detectors and final applications of EMF detector. We hope that you have got a better understanding of this concept or electrical and electronic projects, please give your valuable suggestions by commenting in the comment section below. Here is a question for you, what is the function of the EMF detector?

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