364490000364490180022500ECE 170L Assignment 1
Dr. Mohammed Abdulmajid
We can find a lot of electromagnetism applications in everyday life from domestic appliances to research applications. As we know that the electric field is a field that surrounds electric charges, and the electromagnetic field is a physical field produced by electrically charged objects. Electromagnetism has created a great revolution in the field of engineering applications, it has a great impact on different fields, for example, medical, industrial, home, space, etc.
We know that the electromagnetic field has made a big revelation in the industrial field, and there are a lot of applications has been developed or invented by using the electromagnetic field, such as generators. In the past, the generators work by converting the mechanical energy to electrical energy, but in this days it works under the principle of the electromagnetic field. The generator is a device that generates AC volt by moving the coil inside the electromagnetic field. The main component of it is a rotor, stator, voltage regulator, and rectifier. How the generator work there when the generator start to turning the residual magnetism in the exciter start causing a small amount of alternating current (AC) to be generated in the exciter rotor, the voltage will change to DC by using a three-phase rectifier. The DC, current goes to the main rotor and cases a magnetic field, the main rotor cuts the main stator coils and cause a current to flow to the output terminals T1, T2, and T3. The advantage of the generator repower producing ability, the generator does not require electricity to run. The disadvantage of it generators are very dangerous for our environment, it does not work automatically.
An electric transformer is another application that uses electromagnetic. How it works when a fluctuating electric current flows through a primary coil it generates a magnetic field. Since there is no contact or contact between the primary and secondary parties, the magnetic flux is applied in a magnetic circle between the two ends and when the flow of secondary files reached, the flow of current in these files begins. The strength of the magnetism is directly related to the size of the electric current. There are two type of transformer first step down and second step up, the difference between them is to step down transformer has in the first coil more turns than the second coil, so the seconder has less voltage than the primary. Step up transformer is the opposite. The advantage and disadvantage are high efficiencies, less maintenance cost, easy to move, but it Emits heat and requires a cooling system.
Another example is motor. The motor depends on faraday low for magnetic induction to work. The motor has two main part a stationary part which is the main body and the rotating shaft, the stationary part has permanent magnets and the rotor will be having a winding, the battery will be connected to the winding. When the motor turning on the winding starting to rotate and reacting with the magnet to creating the electromagnetic field.
A microwave oven is a device used to heat food in a few minutes by passing microwave radiation through it. Microwaves are a form of electromagnetic radiation with a frequency higher than radio waves and lower than infrared light. Also, Microwave has a wavelength shorter than radio waves and longer than infrared radiation. Electromagnetic waves that travel through space at the speed of light (3*10^8 m/s). In Microwave Oven, there is a component called magnetron in the cooking chamber. The magnetron is the part that responsible for generating microwaves from electricity inside the microwave oven. Magnetron generates electricity by using the transformer that converts the voltage from 120 volts to about 4000 volts, these voltages will be heating the wire at the center of this magnetron to boiling the electrons. After excitation of electrons happened, electromagnetic waves may be absorbed by matter in many different ways depending on their wavelength.
When someone turns on his cell phone, it is emitting Electromagnetics field (EMFs), especially when using the following wireless communication standards: CDMA, GSM, UMTS, LTE, WIFI, and Bluetooth. In addition, a cell phone emits EMFs even when people don’t use it. There are two types of Electromagnetics field which are microwave electromagnetic radiation from the antenna and more EMFs from the phone body, and both of them are harmful for human.in addition most of the radiation from a phone’s antenna rich go into the adult brain which effects to the memory of the human. Also, this radiation may have led to brain cancer and many other detrimental effects and ailments in their bodies.
A computer is an important device that used now in any home or company. The computer is a device that emits an electromagnetic field. Computers produce at least two types of EMF radiation: Electric fields and Magnetic fields. The device emits strong EMFs when someone close to the computer which means EMF strength decreases with distance, but not only the screen that emits these EMFs but the electronics that inside the device generate a powerful EMF. There is two main low frequency that emitted inside the computer which is the power supply and the disc drive motors. The power supply produces regular EMFs and the disc drive motors generate EMFs only when data reading or writing. In addition, the EMF might be very strong, perhaps 40 or 50 milligauss (mG). These EMFs are very harmful to the human health which means many studies said cancer and other serious diseases have been linked to these EMFs effects.
-698501974850031400751635760Figure: Computer radiation exposure does not just affect the computer user. Computer’s emit various types of electromagnetic frequencies from all directions.
00Figure: Computer radiation exposure does not just affect the computer user. Computer’s emit various types of electromagnetic frequencies from all directions.
The electric bell is a mechanical bell and its work depends on the principle of electromagnetism and produces a repetitive buzzing when a current pass through it. The electric bell consists of six basic things which are: Electromagnet, Armature, Spring, Armature rod, Hammer, and Gong as shown in figure 5. When the switch is pushed ‘on’ should be passing current through a wire (A) and go to the coils of the electromagnetic(D). which has iron cores, and pass out through the metal of the armature. The armature is attached by a flexible steel spring to the framework to make this movement possible. When drawing down the armature and the contact of the screw with the armature spring is broken, and since this contact forms part of the electric circuit, so the current will cease to magnetize the electromagnet. therefore, the armature no longer is attracted and Returns to a non-operating mode as shown in figure 6.
Figure6: Electric bell work
Figure5: The electric bell consists
Medicine is an applied science that benefits from human experience to provide proper treatment throughout history. In modern times, medicine is based on scientific studies documented in laboratory experiments. With the continued progress of medicine has increased the development in this area through the discovery of several applications that accompany this development and the most recent of these applications.
Magnetic resonance imaging (MRI)
The first application, MRI (magnetic resonance imaging) is a medical imaging technique and used in radiology to visualize internal structures. MRI is a source of non-ionizing radiation; for this reason, MRI is safer than X-ray imaging especially for the imaging of children and pregnant women and to detect cancers. To produce the image from this technique should be passing three different fields of EMF which are: A static magnetic field of zero frequency (average magnetic flux density of 1.5–3 Tesla) produced by a large magnet for the alignment of hydrogen nuclei (protons) inside the body. And Low power time-varying magnetic field gradients (100 Hz–1 kHz) generated by small magnets in three orthogonal planes (X, Y and Z directions) to provide the spatial position of the protons and these MF gradients allow focusing on the body part for a patient. Then the last field, RF fields (100–200 MHz) produced in the non-radiative near field of the emitter to excite the protons (in the body) and cause the protons to emit radio waves (radiative RF) for the acquisition of anatomical images. The typical planning for MRI unit divided into: “controlled” areas and “inner controlled” areas as shown in figure 1. The maximum level of the static magnetic fields in the controlled area is kept under 0.5 milliTesla (mT). But the inner controlled area in the immediate vicinity of the imaging equipment, the limit of the static magnetic field is set at 3 mT (30 Gauss). RF shielding surrounding the MRI is placed to prevent exterior RF interferences from affecting the operation of the imaging unit.
Figure 1: The typical planning for MRI unit
Transcranial Magnetic Stimulation (TMS)
The second application, Transcranial Magnetic Stimulation (TMS) is a noninvasive procedure that uses magnetic fields to stimulate nerve cells in the brain to improve symptoms of depression. This technique that allows noninvasive and painless stimulation of the surface of the brain. The technique can also measure brain functions from several aspects such as learning, language, and memory. This technique is based on Faraday’s principle of electromagnetic induction, which is: when electrical current travels through a wire, it creates a magnetic field with a direction perpendicular to the direction of the current as shown in figure 2. In TMS the magnetic fields which perpendicular to electric currents pass through the scalp and cranium relatively unimpeded. Where it is considered the magnetic field acts as a “carrier” of the electrical current needed to stimulate the underlying neurons as shown in figure 3. In addition, this stimulus is much more tolerable than electrical stimulation.
Figure2: When an electrical current (I) runs through a wire, it sets up a magnetic field (B) with a direction perpendicular to the wire.
Figure3: When a current is passing the wires of a TMS coil, the resulting magnetic field passes through the skull and produces an electric current in the brain.
The third application, An X-ray machine is a machine like a giant camera that allows doctors to see what is going on in a patient without having to do surgery. And X-rays are a type of light ray, but the difference between visible light and X-rays is the wavelength of the rays. Human eyes cannot see the light with shorter wavelengths, such as X-rays. To produce an X-ray picture, an X-ray machine produces a very concentrated beam of electrons known as X-ray photons. This beam travels through the air, comes into contact with our body tissues, and produces an image on a metal film. The x-ray black area as shown in figure 4.
Figure4: X-ray picture
In conclusion, we have known a clear aide about how electromagnetic made a big revolution in different field like home, industrial, medical etc, and how this revolution has a good impact, especially in the medical field. in addition, we also know that everything has advantage and disadvantage. For example X-ray, it is very helpful however, it is also very dangers, and some of them has a high cost.