Electromagnetics 11-ES 207

Bhanu PrakashAssoc. ProfessorEEE Department

L- T-P : 3-1-0Credits: 4

Bhanu Prakash @ K L University

Session Learning Objectives: (points to be discussed)

Need of “Electromagnetics (course)” Principle of generation Classification Sources of Electromagnetic waves Advantages & Disadvantages Applications

Bhanu Prakash @ K L University

Need of “Electromagnetics” Study ?Electromagnetic fields (EMF) are all around us. We need them to see, to listen to radio and watch television, to communicate using mobile phones, and to run motors, fans, relays etc.

we generate them every time we turn on a light switch or use an electric appliance.

Bhanu Prakash @ K L University

Faraday's law of induction: (1830s)

Explanation-1 Explanation-2

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How to produce/ generate/ induce Electric Field ?

Bhanu Prakash @ K L University

Electric Fields:

Electric fields arise from voltage (Current Carrying conductor) An electric field can be present even when a device is

switched off. Field strength decreases with distance from the source. Most building materials shield electric fields to some extent.

Bhanu Prakash @ K L University

How to produce/ generate/ induce Magnetic Field ?

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Magnetic Fields:

Magnetic fields arise from current flows. Magnetic fields exist as soon as a device is switched on and

current flows. Field strength decreases with distance from the sources. Magnetic fields are not attenuated by most materials.

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Which of the following is Electric field or Magnetic field or both?

Fig.-4

Fig.-3

Fig.-2

Fig.-1

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Types of Electromagnetic Radiations

• AM and FM radio waves (including TV signals)• Cell phone communication links• Microwaves• Infrared radiation• Light • X-rays• Gamma rays

What distinguishes these from one another?

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i.e. Classification

Type Extremely Low Frequency

Radio Waves Microwaves Infrared

radiationUltraviolet radiation X-rays Gamma rays

Frequency Range 3 Hz – 3 KHz 3 KHz –

300 MHz300 MHz – 300 GHz

300 GHz – 300 THz 300 THz – 30 PHz 300 THz –

30 PHz30 PHz – 30 EHz

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Is there any insulation for Current?

Is there any insulation for Field (Flux) ?

Bhanu Prakash @ K L University

Which is most liking place in your Home?

Kitchen room

Hall

Bed room

Bathroom

Bhanu Prakash @ K L University

Sources of Electromagnetic fieldsFrequency Range Type Common Sources

3 Hz – 3 KHz Extremely Low Frequency Power lines, appliances, electronics

3 KHz – 300 MHz Radio Waves AM/FM radio, television broadcasting, CB radios

300 MHz – 300 GHz MicrowavesCell phones, wireless internet, satellite broadcasting, microwave ovens, radar, medical imaging

300 GHz – 300 THz Infrared radiation Lasers, alarm systems, motion detectors

300 THz – 30 PHz Ultraviolet radiation Fluorescent and incandescent lights

300 THz – 30 PHz X-rays X-ray medical imaging30 PHz – 30 EHz Gamma rays Nuclear material

Bhanu Prakash @ K L University

Sources of Electromagnetic fields Contd……

computers and related equipment

computer screens (especially the older types),

information networks electrical appliances

(including TV's) electronic equipment Cell phones cell phone masts radio and TV transmitters

microwave ovens microwave transmitters or

ovens, house-wiring high and low voltage power

lines cars, motor cycles, buses,

trains, planes. high voltage transformers, transmission cables & Lines pylons.

Bhanu Prakash @ K L University

Bhanu Prakash @ K L University

What are the sources of EM waves in this Lecture hall?

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Field distributions

Electromagnetic fields inside a desktop computer

Electromagnetic fields inside a Motor

The H-field on the whole surface of an airplane

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Disadvantages

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Which is most liking place in your Home?

Kitchen room

Hall

Bed room

Bathroom

Bhanu Prakash @ K L University

Electromagnetic field radiation (EMF) is emanating from virtually every single electrical appliance, computer, electric wire, and especially high voltage lines (overhead and buried), which are carrying current.

EMF is specifically causing cancer in children and in older adults and may be triggering countless other immune deficiency and psychological diseases and disorders in anyone in close proximity.

Many scientists warn people not to live within 200 yards (190m) of high voltage power lines.

Of 35 international research studies on electric field radiation, 33 established a conclusive link between brain tumors, leukemia, and other forms of cancer.

Bhanu Prakash @ K L University

The Bedroom Is Often the Most Dangerous Place In the Home

Many researchers and scientists now feel that electromagnetic field radiation, both from within and without the bedroom, is the single biggest factor in poor sleep. And poor health.

Look around your bedroom. Is there a clock radio on the nightstand near your pillow? A TV? A stereo?A cell phone below the pillow (bedmate)?A Laptop near to you/ your bed? Are there high voltage power lines with close to your residence? All or any of these electric sources can ruin your sleep and can substantially increase your risk of developing cancer and any number of diseases, both psychological and physical.

Bhanu Prakash @ K L University

While you sleep, your body relaxes and is unconscious. In this state

of vulnerability, research indicates you are 100-150 times more

open to the damage of electromagnetic radiation that when you are

awake. Children are often up to 1,000 times more sensitive to these

fields when they are asleep. (TV screen in your bedroom will radiate

energy all night...even after it has been unplugged. It can take hours

or even days for the built-up voltage in the television to dissipate. )

Do not leave any thing plugged in while you sleep, even if it is

turned off. Outside high voltage power lines continually radiate EMF

24 hours a day.

Bhanu Prakash @ K L University

Biological Effects of Electromagnetic Radiation

Protein Changes in Skin Excited Brain Cells DNA Damage Brain Cell Damage Aggressive Growth in Leukemia Cells Increased Blood Pressure

Harmful Effects of ElectroMagnetic Radiation

Salivary Gland Cancer Brain Tumour Lymphatic Cancer and Bone Marrow Cancer Miscarriage Asthma

Bhanu Prakash @ K L University

Bhanu Prakash @ K L University

Size of the Substati ons

11KV/132KV

132KV/33KV

132KV/11KV

33KV/11KV

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Advantages

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Easy to generate, use, and applicable in many implements.

Easy hand rules to understand flow direction, force, and polarity too.

Can be used in incredibly small to very large situation (i.e. pacemakers or trains)

Electromagnetic energy is clean. It is not polluting

Bhanu Prakash @ K L University

Applications:• Motors and generators• Transformers• Relays• Electric bells• Loudspeakers• Magnetic recording and data storage equipment: tape recorders, VCRs,

hard disks• Scientific instruments such as MRI machines and mass spectrometers• Particle accelerators• Magnetic locks• Magnetic separation of material• Industrial lifting magnets• Electromagnetic suspension used for MAGLEV trains

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Applications: Contd….

• Radars• Cooking (with microwaves)• Medical Imaging (X rays)• “Night Vision” (infrared)• Astronomy (radio, wave, IR, visible, UV, gamma)• Satellite Communication• TV Communication• Wireless Communication• Mobile Communication• Microwave Communication• This theory is also used in analysis and designing of antenna, transmission lines and wave guides.

All that we experience through our eyes is conveyed byelectromagnetic radiation…

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Applications: (Medical) Contd….

• Magnetic resonance imaging used in diagnostic. In this case is used a static magnetic field (a few Tesla) with a radio frequency signal superimposed

• Hyperthermia uses electromagnetic fields for the treatment of cancer by means of tissue heating;

• Electric stimulation: the stimulation of the hippocampus by means of electric field can be used in some brain therapy like Parkinson or neurological diseases.

• Pulsed electromagnetic fields can affect the osteoblaste proliferation for bone reparation and favorite the wound healing.

Bhanu Prakash @ K L University

Points discussed : (Summary)

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Doubts/Questions?Doubt is worst Enemy!

If you still have enemies Send them to

bhanu184@kluniversity.in