Electromagnetics Electromagnetics 11-ES 207 Bhanu Prakash Assoc. Professor EEE Department L- T-P : Credits: 4

Session Learning Objectives: (points to be discussed) Need of “Electromagnetics (course)” Principle of generation Classification Sources of Electromagnetic waves Advantages & Disadvantages Applications Bhanu 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 K L University

Faraday's law of induction: (1830s) Explanation-1 Explanation-1 Explanation-2Explanation-2 Bhanu K L University

How to produce/ generate/ induce Electric Field ? Bhanu 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 K L University

How to produce/ generate/ induce Magnetic Field ? Bhanu K L University

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. Bhanu K L University

Which of the following is Electric field or Magnetic field or both? Fig.-4 Fig.-3 Fig.-2 Fig.-1 Bhanu K L University

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? Bhanu K L University

i.e. Classification Bhanu K L University

Is there any insulation for Current? Is there any insulation for Field (Flux) ? Bhanu K L University

Which is most liking place in your Home? Kitchen room Hall Bed room Bathroom Bhanu K L University

Sources of Electromagnetic fields Bhanu 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 K L University

What are the sources of EM waves in this Lecture hall? Bhanu K L University

Field distributions Electromagnetic fields inside a desktop computer Electromagnetic fields inside a Motor The H-field on the whole surface of an airplane Bhanu K L University

Disadvantages

Which is most liking place in your Home? Kitchen room Hall Bed room Bathroom Bhanu 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 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 K L University

 While you sleep, your body relaxes and is unconscious. In this state of vulnerability, research indicates you are 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 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 K L University

Size of the Substations 11KV/132KV 132KV/33KV 132KV/11KV 33KV/11KV Bhanu K L University

Advantages

 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 K L University

Applications: Motors and generators Motorsgenerators Transformers Relays Electric bells Loudspeakers Magnetic recording and data storage equipment: tape recorders, VCRs, hard disks Magnetic recordingtape recordersVCRshard disks Scientific instruments such as MRI machines and mass spectrometersMRImass spectrometers Particle accelerators Magnetic locks Magnetic separation of material Magnetic separation Industrial lifting magnets Electromagnetic suspension used for MAGLEV trains Electromagnetic suspension Bhanu K L University

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 by electromagnetic radiation… Bhanu K L University

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 K L University

Points discussed : (Summary) Bhanu K L University

Doubts/Questions? Doubt is worst Enemy! If you still have enemies Send them to bhanu Bhanu K L University