Electromagnetic Interference

What is Electromagnetic Interference & its Sources of EMI production?

Welcome to all students in my latest blog post. Today we will discuss about EMI mean Electromagnetic Interference. You have heard many a times about EMI & EMC (Electromagnetic Compatibility) combined but, in this post, we are going to talk about on EMI. We will provide you separate video for EMC to get your concepts clears about this topic also.

EMI topic is very important and popular also and it has to be very clear to understand its concepts. As you all know that we believe in concepts 😊. Let’s start our topic in a very simple and easy way to get you more understanding about this topic.

You know about the triangle which is very well known in electromagnetism. In this triangle, vertices are indicated as Source, Victim and Coupling Path (As shown in figure). Now we will discuss about these vertices in detail. Let’s have a daily routine example to understand this Source, Victim and Coupling Path terms.

Electromagnetic Interference

We know that human body behave abnormal during any infection/disease which is surely caused by any infecting object. Suppose human body infected by mosquito and received malaria disease due to this. In this example, mosquito is Source, the human body is Victim and bite of mosquito which caused infection is Coupling Path. Now, we will explain this example analogy in electrical system.

As we know that this Electromagnetic Interference generally malfunctioned our electronics/semiconductor-based equipment in which IGBT’s, GTO’s, MOSFET’s are used and they are very sensitive to this EMI exposure.

Let’s talk about EMI sources in electrical system first which are caused of this phenomenon and malfunction our electronics-based equipment.

Electromagnetic Interference
  • Coil:

As an electrical engineering student, supposed to be, we know that whenever we apply voltage to any coil, it gets energized and stablish a well-defined magnetic field around itself. We also know about the Electromagnetic Induction that is, “when any changing magnetic field cuts any current carrying conductor, it will induce EMF in that conductor also”, this induced EMF will establish increase or decrease effect in that current carry conductor which will be cause of malfunctioning of that receiving-end equipment. Suppose that current carrying conductor is responsible for the voltage of electronics circuit in which there are many semiconductor-based components are present. If this wire gets drop in voltage due to this EMI phenomenon, then the equipment will malfunction and system will not be stable.

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  • Frequency:

As a telecom engineering student, branch of electrical, we all know that all types of telecommunications are based on high frequency. In earlier days, Radio and Television use low rang frequencies for communication but this communication also disturbed by other high frequencies present in the system and we may have bad voice or video results on radio or television respectively. Now a days, mobile phone communication is carried out on very high frequencies. Many techniques and methods are being used to cope the high frequency interferences in mobile communications but in spite of all these, interference interrupts the signals. This high frequency mobile communication also interrupts our electrical system in overhead lines and it results as corona effect increase in overhead transmission lines.

  • Leakage Current:

The 3rd type of EMI source is leakage current. This leakage current also flow in body of sensitive equipment and most of the time it gets path to the ground of the electronic circuits. Due to this interference with electronic components, it causes malfunctioning of these semiconduction-based components.

  • High Voltage Cable:

As electrical engineering students we are very much familiar with the phenomenon of MMF (Magnetomotive Force) in high potential overhead ac transmission lines. If any low voltage dc current carry wire passes near to this high voltage power transmission line, it will get interference in dc voltages and it will reduce the performance of equipment.


  • Tube Light:

As all we know that tube lights have choke which are coiled based and produce magnetic interference for sensitive equipment. So, that is the reason why we don’t use choke-based tube lights in that room where sensitive and expensive equipment are used.


That all, we have for you in this post/article at the moment. This is very basic explanation presented in this post. Your valued comments are appreciated to know about our posts. Share with your classmates and electrical engineering community.

Have a good day 😊

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