Circuit Lab Report Essay

Ohm’s Law is V = I * R or in some cases I = V / R. The next two laws were established by a German physicist by the name of Gustav Kirchhoff. Kirchhoff’s first law is his voltage law. Kirchhoff’s Voltage Law (KVL) states that around any loop in a circuit, the voltage rises must equal the voltage drops. The next law that Kirchhoff introduced was his current law. Kirchhoff’s Current Law (KCL) states that the total current entering a junction must equal the total current leaving the junction.

These laws, however, cannot be proven or tested without the aid of a multimeter. A multimeter is an instrument designed to measure electric current, voltage, and usually resistance, typically over several ranges of value. The multimeter has different programs to measure voltage, current, resistance, etc. produced from one of two types of circuits.

The first type of circuit is a series circuit. A series circuit is a circuit in which the components are arranged end to end in such a way that the electric current flows through the first component, through the next component, and so on, until it reaches the source again.

In contrast, a parallel circuit is a circuit in which the has more than one resistor and has multiple paths to move along. The main purpose of this lab was to prove the laws of Ohm and Kirchhoff. On another note, being able to take part in this lab taught my partner and I the fundamental skills of constructing series and parallel circuit and using a multimeter to calculate the current and voltage of a circuit.

I believe that if we only have the basic materials to conduct electricity (such as resistors, alligator clip, cords, a multimeter, and a power source), then we can still prove the that the laws that Ohm and Kirchhoff established are in fact reliable sources for calculating data regarding certain electrical circuits. I’ve reached this hypothesis because Ohm’s laws and Kirchhoff’s two laws are supposed to be laws used for any electrical circuits. Based on this, these three laws should be able to be validated with this experiment.

Materials
– Power Source
– Alligator Clips
– 1,000 Ohms Resistor
– 10,000 Ohms Resistor
– Multimeter

Methods
Ohm’s Law

1. Assemble circuit as seen in figure 1 and set the multimeter to current 2. install series in the circuit and set the power supply to 3, 4.5, 6, 7.5 3. record number on multimeter and compare to the calculated current using Ohm’s law

Kirchhoff’s Voltage Law

1. assemble circuit as seen in figure 2 and set multimeter to volts 2. install in parallel over both resistors and set the power supply to 3, 4.5, 6, 7.5 3. record number on multimeter and see if the total voltage dropped equals voltage added

Kirchhoff’s Current Law
1. Assemble circuit as seen in figure 3 and set multimeter back to current 2. install at all three points at both junctions 3. see if the current entering the junction is equal to the current leaving the junctions

Discussion

Our lab in general, went fairly well. We took our time and did not rush through this lab, so we could get the best results, but we did have some trouble with our Multimeter on more than one occasion. For example, while we were attempting to prove Ohm’s Law and Kirchhoff’s Voltage Law. The Multimeter, at first was acting up and completely just not working, but we then realized that it was not set on the correct measuring task. Then, on the same two labs, we were getting readings from the Multimeter that made no sense. It told us that the current for the circuit was 967.83 Ohms which for the type of circuit that we built, was impossible.

After fixing the problem with the Multimeter and proving Ohm’s Law and Kirchhoff’s Voltage Law, we moved onto the Current Law that Kirchhoff established. This time, the problem wasn’t the Multimeter, or the resistors, or the power supply, or anything else. It was us. We were overall a bit confused on how the circuit was created and it took a long time to eventually construct and then prove. Even though the problems were an annoyance, the lab was very insightful and taught us a lot about electric currents and circuits.

Conclusion

At the conclusion of this experiment, our results supported our hypothesis greatly even though our numbers were not a hundred percent on point. But there is room for error, like the fact that the power supply was not great quality and doesn’t give exactly 3 volts or 4.5 volts or any of that. Also, the resistors are not high-quality resistors and are also worn down from years of use, so they don’t give exactly 1,000 / 10,000 Ohms like we were looking for. Other sources of error included the Multimeter, which was not exact because the Multimeter rounds numbers, the Alligator clips, which are (like the power supply and resistors) not the best and shed energy, and our calculations, which could have suffered from any addition or multiplication or division error.

George Westinghouse Essay

The Westinghausen family tree stretches back to that of the ninth century in Westphalia, Germany. Some of the family decided to emigrate to Europe and later settle in the United States. In the nineteenth century, George Westinghouse decided to move all over the former United States and settled in Central Bridge, New York where he had George Westinghouse II. Born into a family of ten (which would become twelve later on) on October 16, 1846, George Westinghouse Jr. (son of George Westinghouse and Emmeline Vedder) was born into an agricultural family.

George Jr.’s father moved the family to Schenectady to sell farming tools. After serving the Union Army for three years at the age of fifteen, George II (later to be referred to as just George) attended college for three months (dropping out because he believed that he could learn much more about machinery on his own). During his three-month stay however, George had obtained a patent for a rotary steam engine (which he received in 1865).

George’s inventions kept coming, such as his invention that allowed derailed railroad cars to be placed back onto their tracks. George then married Marguerite Erskine in Brooklyn, New York and had a child, George Westinghouse III. George and his new family moved to Pittsburgh, where he made a deal with a steel company, that had a better capital than his ex-business partner, to make his reversible cast-steel frog for a cheaper cost. His newer inventions then switched to being directly helpful to the train, such as using air-compressed brakes that worked indirectly.

After improving upon this invention for a while, George opened many companies, such as the Westinghouse Air Brake Company and the Union Switch & Signal Company. Both of these companies focused on helping railroads and making sure his inventions worked the way they were suppose to. When George’s property was having a well drilled, something unexpected happened. This well produced a natural supply of gas on accident. George became interested in gas after this discovery and made the Philadelphia Co. Westinghouse, which supplied gas to private houses. Later, George became interested in electricity and its many uses.

Influenced by Thomas Edison’s flaws of his directed current (DC) electricity, George obtained patents for the inventions of alternating current (AC). Hiring Nikola Tesla (a Serbian-American electrical engineer) and William Stanley (an American physicist), George wanted tests run on a “secondary transformer” to make sure it was efficient. After tests to make sure that it was efficient enough, George went into competition with Thomas Edison’s DC electricity by making the Westinghouse Electric Company in 1886. George then started to win many contracts from Edison to provide power, contracts such as Chicago’s World Fair of 1893 or installing hydro-powered generators at Niagara Falls (completed in 1895).

To install hydro-electric harvesters Even though George’s company was built on Edison’s DC faults (such as power plants having to be placed every couple miles apart), George’s company was not without it’s own faults. The Westinghouse Electric Company did employ more than 500,000 people but it had to file for bankruptcy twice and after filing for bankruptcy twice, he stepped down as head honcho. Within four years of stepping down, George began to cut all ties with his electric company, believing he was expending too much on the company to receive an income. Later, on March 2, 1914, was to be discovered dead alongside a blueprint for an electric wheelchair and on June 23 1914, his wife [Marguerite Erskine] died and was buried next to him in the Arlington Cemetery in Washington D.C.

Importance of electrical services in buildings Essay

Electricity has been part of our lives. It has brought many things that surely have made many wonders and life would seem so hard without it. Electricity powers our light, heating, electronic appliances such as computers and television, and a host of essential services that we take for granted. However, electricity has much more important aspects because it is a fundamental feature of all matter. Electricity is the force that holds together the molecules and atoms of all substances. The type of electricity that is most familiar to us is electrical current.

This is the flow of electrical charges through a substance called a conductor such as a metal wire. This flow happens beacuse some of the negatively charge electrons circling the nuclei of the conductor’s are held loosely. The electrons can move from one atom to the next, producing and electrical current.

Electricity has become something we rely on to live our lives, but it was by no means an overnight discovery.

Over the last two hundred years it has developed from a scientific phenomenon to part of everyday life. One of the first applications of electricity was the first incandescent light bulb in around 1870.

The electric overhaul of society obviously brought many fresh new dangers with it, but it eliminated some of the old ones, like the naked flames of gas lighting that was commonly used in homes and factories then.

The Joule heating effect that can be found in light bulbs is also present in electric heating. Electric heating has been thought of as wasteful in the past because in order to create that heat energy, heat has already been used in the power stations

Denmark (among a few other countries) has issued a new law restricting electric heating use in new buildings, if allowed at all. As well as heating, electricity provides a hugely beneficial source of refrigeration. As temperatures get hotter, the demand for air conditioning gets higher, increasing the amount of energy used, and so climate change is increasing in a snowball effect.

Electricity is of course used in telecommunication. The electrical telegraph was one of the earliest applications that electricity was used for, commercially demonstrated by Crooke and Wheatstone in 1837.

Electrical Circuit Essay

1. Conductor – is a material which contains movable electric charges. In metallic conductors such as copper or aluminum, the movable charged particles are electrons (see electrical conduction). Positive charges may also be mobile, such as the cationic electrolyte(s) of a battery, or the mobile protons of the proton conductor of a fuel cell. In general use, the term “conductor” is interchangeable with “wire. 2. Insulators – are non-conducting materials with few mobile charges and which support only insignificant electric currents. 3. Atom – is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons.

The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutrons). 4. Electric charge – is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two negatively charged objects.

Positively charged objects and negatively charged objects experience an attractive force. 5. A simple circuit contains the minimum things needed to have a functioning electric circuit. A simple circuit requires three (3) things:

* A source of electrical potential difference or voltage. (typically a battery or electrical outlet) * A conductive path which would allow for the movement of charges. (typically made of wire) * An electrical resistance (resistor) which is loosely defined as any object that uses electricity to do work. (a light bulb, electric motor, heating element, speaker, etc.) 6. Electrical circuit – is a path which electrons from a voltage or current source follow. Electric current flows in a closed path called an electric circuit. The point where those electrons enter an electrical circuit is called the “source” of electrons. The point where the electrons leave an electrical circuit is called the “return” or “earth ground”.

The exit point is called the “return” because electrons always end up at the source when they complete the path of an electrical circuit. The part of an electrical circuit that is between the electrons’ starting point and the point where they return to the source is called an electrical circuit’s “load”. 7. Ohm’s law – says that in an electrical circuit, the current passing through a resistor between two points, is related to the voltage difference between the two points, and inversely related to the electrical resistance between the two points. This relation is shown in the following formula:

where I is the current in amperes, V is the potential difference in volts, and R is a constant, measured in ohms, called the resistance.

It also says that current is directly proportional to voltage loss though a resistor. That is if current doubles then so does voltage. To make a current flow through a resistance there must be a voltage across that resistance. Ohm’s Law shows the relationship between the voltage (V), current (I) and resistance (R). It can be written in three ways:

Does Electricity Move Better Through Thick Wires or Thin Ones Essay

My research is to determine if electricity moves better through thick wires or through thin wires. For this experiment I used two size D batteries, two flashlight bulbs, one 6.5 inch thin steel wool piece, one 6.5 inch thick steel wool piece, two 2 inch pieces of straw, and some electrical tape. Steel wool is a material made from thin fibers of steel made into a pad. (http://www.wisegeek.com/l-what-is-steel-wool.htm) There are many uses for steel wool. It can be used for sanding furniture, removing paint finishes; it can be used as a scouring pad for pots and pans and as rodent control.

(http://wisegeek.com/what-are the-different-uses-for-steel-wool.htm)

For this experiment it was used as a conductor of electricity. (http://ehow.com/list_6545332_electrical-properties-steel.html)

The batteries were used to provide power for the light bulbs. The steel wool pieces were used for transferring the electricity used to power the light bulbs. Each of the steel wool pieces were taped to the negative side of the batteries.

The other ends of the steel wool wires were taped to the base of the light bulbs. The light bulbs were then lit by placing the bulbs on the positive side of the batteries. I did this experiment five times for each steel wool piece. I set a timer for one minute and turned the light off in my room to see which light bulb would be brighter. After the first minute was over the light bulb with the thin wire was brighter than the light bulb with the thick wire.

During the second minute the light bulb with the thick wire ended up being brighter. In the third minute the bulb with the thin wire was brighter than before. The light shining from bulb with the thick wires stayed the same. After the fourth minute was over the bulb with the thin wires became dull. The bulb with the thick wires did not change. Lastly after the fifth minute both bulbs stayed the same. After comparing this data I think that electricity works better through thick wires. The measurement of how difficult electrical current travels through material is called electrical resistance. (http://www.education.com/science-fair/article/resistance/)

The electrical current did not move faster through the steel wool pads because both bulbs came on at the same time. The thinner wire had more resistance and less electric current going through it. (http://www.education.com/science-fair/article/resistance/) Based on the results of my experiment I conclude that the use of thicker wires only helps produce a stronger electrical current.

AC Circuits Essay

Discussion

In the experiment AC circuits, the purpose was to see the effect that a capacitor, resistor, and inductor have on the voltage, and current of a circuit. We created circuits with 2 resistors, a capacitor and a resistor, and then a capacitor, resistor, and an inductor. The circuits were then hooked up to a function generator, and oscilloscope to find the voltage across certain frequencies and then calculate the peak current, capacitive reactance or the inductive reactance, and phase difference.

When beginning the experiment, we measured the resistance of both resistors with a digital multi-meter and received values for R1 as 559 Ω +or- 10 Ω and for R2 as 108 Ω +or- 10 Ω.

After measuring the resistance, we placed each of them in series on a circuit board and we increased the frequency four different times ranging from 100 Hz to 5,000Hz and measured the voltage across each resistor and determined the phase relationship. We then replaced the 559 Ω resistor with a 1μF capacitor, where we performed a similar process, only this time we increased the frequency eight times, ranging from 100 Hz to 5,000 Hz measuring the voltage across the capacitor and resistor, and finding the value for Δ t.

We then calculated the peak current, capacitive reactance, and phase difference, and then graphed the reactive capacitance vs. the period to get a slope (3731.3) and then determine an experimental value for the capacitance (4.2654*10^-5 F) where we then calculated the percent difference (96.52%). Next, we replaced the capacitor with an inductor, repeated the same process, except rather than measuring capacitive reactance, we measured inductive reactance, and then plotted inductive reactance vs. the frequency and used the slope (.0185) to calculate the value for L (.0306). Next, we added the capacitor back into circuit, aligning them all in series where we repeated the process finding the voltages across the inductor, capacitor, and resistor, then graphed the current vs. the frequency. I then went back and determined the percent difference between the resonant frequency based on theory (8926.766 Hz) and the experimental resonant frequency (1374.9259 Hz) and got a value of 146.614%.

In regards to the error, the majority came from the possibility that our circuit was improperly set up, causing to the current to essentially bypass the resistors. Part of the discrepancies in the percent difference with the capacitance is because the manufacturers staple a 20% uncertainty to the1μF capacitor, as for the rest of the percent difference; I again contribute it to a flaw in our circuit set up. In determining the experimental value for the resonant frequency, we derived this value from using information from the graphs. I believe if our graphs had been more accurate, it would have resulted in a much more accurate value that lays closer to the theoretical value. Another possibility for error is that inductors have their own resistances that we ignore for the sake of simplicity. The added resistance from the inductor was not factored into any of our measurements. Also, it should be noted error might stem from imperfect scope readings.

Knowledge gained from this lab will allow me to approach circuits much more thoroughly and build conclusions from very little provided information. For instance if I came across an AC circuit that had a 500 Hz frequency and that had a resistor and EITHER a capacitor OR an inductor, I would be able to determine the remaining component from information about the voltage in different places. If the voltage across the circuit leads the voltage across the resistor, I would know that the remaining component is an inductor. Likewise, if the circuit voltage lags the resistor voltage, I would know that the remaining component is a capacitor. However if the circuit could have a capacitor AND an inductor, I would require more information in order to determine the circuit’s composition.

Load Sheeding Essay

Power generators have limited capacities. When demand of electricity in a certain area exceeds its generation, the supply is to be cut temporarily as a method of reducing the demand on the generators. This temporary reduction in electricity supply is known as load shedding and less formally power cut. Peak load shedding hours are early evenings and mornings when most bulbs are lit and most home appliances are in use. Power is a very important daily need of modern life. Without it, life cannot run normally.

Radios, TVs, computers, rice cookers and other home appliances don’t operate. With power cut, supply of drinking water, etc. is halted. Rooms cannot be heated or cooled. Records are lost and valuable machines break down when the power cut is sudden and uninformed. Nights sinks in complete darkness with no bulb illuminating. People with criminal motives are active in load shedding hours at night. Narrow passages and streets are very insecure.

Road accidents go up.

Electrically powered vehicles are halted. Schools and colleges cannot give their morning and evening classes particularly and students cannot do their homework either. Even emergency batteries cannot be full-charged in the time of long- hour load shedding. Shrinking entertainment and recreational opportunities force people to stay idle and bored. Regular load shedding has very serious impact in the overall economic activities of a country. Overall earning opportunities for the people are limited. Factory productions fall and markets shrink. Running cost of business corporations such as, cinemas, hotels and lodges rises enormously as they e by generating power through diesel-fed generators. As a result their business falls or the price increases. However, battery makes and traders make their good days. Even the sale of candles goes up.

Despite its rich potential for hydropower, there is not enough power available in Nepal. Limited large-scale hydro- projects are based on snow-fed rivers or natural ponds collecting rainwater. Load shedding is growing with expanding cities and overambitious transmissions. Even in rainy seasons, our generators cannot produce enough to meet the demands. The are worse in dry winter when power is available for less one third of the day. It’s a real irony that Nepal with the potential of 83,000 MW of hydroelectricity has regular and long-hour load shedding.

This is the result of our irresponsible leadership which otherwise would have worked at least to meet the internal demand, if not for export. Now it is very urgent to make both short-term and long-term efforts for eliminating load shedding. Immediate demands can be fulfilled only by importing power from neighbors. So consumers must be made aware about the need of minimizing the power consumption and its vital methods. Production should be raised in every possible way. At the same time must also look further ahead. Utilizing foreign aid, sole large-scale projects should be started immediately so that e needs will be fulfilled more easily. We should invite foreign investment in this sector, too and start small-scale with local efforts.

Biography of Georg Simon Ohm Essay

Georg Simon Ohm (16 March 1787 – 6 July 1854) was a Bavarian (German) physicist and mathematician. As a high school teacher, Ohm began his research with the new electrochemical cell, invented by Italian scientist Alessandro Volta. Using equipment of his own creation, Ohm found that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current. This relationship is known as Ohm’s law. Ohm died in Munich in 1854, and is buried in the Alter Südfriedhof.

Early years

Georg Simon Ohm was born into a Protestant family in Erlangen, Bavaria, (then a part of the Holy Roman Empire)son to Johann Wolfgang Ohm, a locksmith and Maria Elizabeth Beck, the daughter of a tailor in Erlangen. Although his parents had not been formally educated, Ohm’s father was a respected man who had educated himself to a high level and was able to give his sons an excellent education through his own teachings. Of the seven children of the family only three survived to adulthood: Georg Simon, his younger brother Martin, who later became a well-known mathematician, and his sister Elizabeth Barbara.

His mother died when he was ten. From early childhood, Georg and Martin were taught by their father who brought them to a high standard in mathematics, physics, chemistry and philosophy. Georg Simon attended Erlangen Gymnasium from age eleven to fifteen where he received little in the area of scientific training, which sharply contrasted with the inspired instruction that both Georg and Martin received from their father. This characteristic made the Ohms bear a resemblance to the Bernoulli family, as noted by Karl Christian von Langsdorf, a professor at the University of Erlangen.

Life in university

Georg Ohm’s father, concerned that his son was wasting his educational opportunity, sent Ohm to Switzerland. There in September 1806 Ohm accepted a position as a mathematics teacher in a school in Gottstadt bei Nydau. Karl Christian von Langsdorf left the University of Erlangen in early 1809 to take up a post in the University of Heidelberg and Ohm would have liked to have gone with him to Heidelberg to restart his mathematical studies. Langsdorf, however, advised Ohm to continue with his studies of mathematics on his own, advising Ohm to read the works of Euler, Laplace and Lacroix. Rather reluctantly Ohm took his advice but he left his teaching post in Gottstadt bei Nydau in March 1809 to become a private tutor in Neuchâtel. For two years he carried out his duties as a tutor while he followed Langsdorf’s advice and continued his private study of mathematics. Then in April 1811 he returned to the University of Erlangen.

His private studies had stood him in good stead for he received a doctorate from Erlangen on 25 October 1811 and immediately joined the staff as a mathematics lecturer. After three semesters Ohm gave up his university post. He could not see how he could attain a better status at Erlangen as prospects there were poor while he essentially lived in poverty in the lecturing post. The Bavarian government offered him a post as a teacher of mathematics and physics at a poor quality school in Bamberg and he took up the post there in January 1813. This was not the successful career envisaged by Ohm and he decided that he would have to show that he was worth much more than a teacher in a poor school. He worked on writing an elementary book on the teaching of geometry while remaining desperately unhappy in his job.

After Ohm had endured the school for three years it was closed down in February 1816. The Bavarian government then sent him to an overcrowded school in Bamberg to help out with the mathematics teaching. On 11 September 1817 Ohm received an offer of the post of teacher of mathematics and physics at the Jesuit Gymnasium of Cologne. This was a better school than any that Ohm had taught in previously and it had a well equipped physics laboratory. As he had done for so much of his life, Ohm continued his private studies reading the texts of the leading French mathematicians Lagrange, Legendre, Laplace, Biot and Poisson. He moved on to reading the works of Fourier and Fresnel and he began his own experimental work in the school physics laboratory after he had learnt of Oersted’s discovery of electromagnetism in 1820. At first his experiments were conducted for his own educational benefit as were the private studies he made of the works of the leading mathematicians.

The Jesuit Gymnasium of Cologne failed to continue to keep up the high standards that it had when Ohm began to work there so, by 1825, he decided that he would try again to attain the job he really wanted, namely a post in a university. Realising that the way into such a post would have to be through research publications, he changed his attitude towards the experimental work he was undertaking and began to systematically work towards the publication of his results [1]:- Overburdened with students, finding little appreciation for his conscientious efforts, and realising that he would never marry, he turned to science both to prove himself to the world and to have something solid on which to base his petition for a position in a more stimulating environment. In fact he had already convinced himself of the truth of what we call today “Ohm’s law” namely the relationship that the current through most materials is directly proportional to the potential difference applied across the material.

The result was not contained in Ohm’s firsts paper published in 1825, however, for this paper examines the decrease in the electromagnetic force produced by a wire as the length of the wire increased. The paper deduced mathematical relationships based purely on the experimental evidence that Ohm had tabulated. In two important papers in 1826, Ohm gave a mathematical description of conduction in circuits modelled on Fourier’s study of heat conduction. These papers continue Ohm’s deduction of results from experimental evidence and, particularly in the second, he was able to propose laws which went a long way to explaining results of others working on galvanic electricity. The second paper certainly is the first step in a comprehensive theory which Ohm was able to give in his famous book published in the following year.

Teaching career

Ohm’s own studies prepared him for his doctorate which he received from the University of Erlangen on October 25, 1811. He immediately joined the faculty there as a lecturer in mathematics but left after three semesters because of unpromising prospects. He could not survive on his salary as a lecturer. The Bavarian government offered him a post as a teacher of mathematics and physics at a poor quality school in Bamberg which Ohm accepted in January 1813. Unhappy with his job, Georg began writing an elementary textbook on geometry as a way to prove his abilities. Ohm’s high school was closed down in February 1816. The Bavarian government then sent him to an overcrowded school in Bamberg to help out with the teaching of mathematics.

Memorial for Ohm at the Technical University of Munich, Campus Theresienstrasse After his assignment in Bamberg, Ohm sent his completed manuscript to King Wilhelm III of Prussia. The King was satisfied with Ohm’s book, and offered Ohm a position at the Jesuit Gymnasium of Cologne on 11 September 1817. This school had a reputation for good science education and Ohm was required to teach physics in addition to mathematics. The physics laboratory was well-equipped, allowing Ohm to begin experiments in physics. As the son of a locksmith, Ohm had some practical experience with mechanical devices. Ohm published Die galvanishe Kette, mathematisch bearbeitet (The Galvanic Circuit Investigated Mathematically) in 1827. Ohm’s college did not appreciate his work and Ohm resigned from his position. He then made an application to, and was employed by, the Polytechnic School of Nuremberg. Ohm arrived at the Polytechnic School of Nuremberg in 1833, and in 1852 he became a professor of experimental physics at the University of Munich.

The discovery of Ohm’s law
Further information: Ohm’s Law

Ohm’s law first appeared in the famous book Die galvanische Kette, mathematisch bearbeitet (tr., The Galvanic Circuit Investigated Mathematically) (1827) in which he gave his complete theory of electricity. In this work, he stated his law for electromotive force acting between the extremities of any part of a circuit is the product of the strength of the current, and the resistance of that part of the circuit. The book begins with the mathematical background necessary for an understanding of the rest of the work. While his work greatly influenced the theory and applications of current electricity, it was coldly received at that time.

It is interesting that Ohm presents his theory as one of contiguous action, a theory which opposed the concept of action at a distance. Ohm believed that the communication of electricity occurred between “contiguous particles” which is the term Ohm himself used. The paper is concerned with this idea, and in particular with illustrating the differences in this scientific approach of Ohm’s and the approaches of Joseph Fourier and Claude-Louis Navier. A detailed study of the conceptual framework used by Ohm in producing Ohm’s law has been presented by Archibald. The work of Ohm marked the early beginning of the subject of circuit theory, although this did not become an important field until the end of the century.

Ohm’s acoustic law

Further information: Ohm’s acoustic law

Ohm’s acoustic law, sometimes called the acoustic phase law or simply Ohm’s law, states that a musical sound is perceived by the ear as a set of a number of constituent pure harmonic tones. It is well known to be not quite true.

WORKS

* Guidelines for an appropriate treatment of geometry in higher education at preparatory institutes / notes
* The Galvanic Circuit Investigated Mathematically
* Elements of analytic geometry concerning the skew coordinate system
* Fundamentals of physics: Compendium of lectures

The History of Electric Transformer Essay

Transformer is a device that transfers electric energy from one circuit to another, usually with a change in voltage. Transformers work only with a varying electric current, such as alternating current (AC). Transformers are important in the distribution of electric power. They raise the voltage of the electricity generated at a power plant to the high levels needed to transmit the electricity efficiently. Other transformers reduce the voltage at the locations where the electricity is used. Many household devices contain transformers to raise or lower house-current voltage as needed.

Television sets and stereo equipment, for example, require high voltages; doorbells and thermostats, low voltages. A simple transformer consists essentially of two coils of insulated wire. In most transformers, the wires are wound around an iron-containing structure called the core. One coil, called the primary, is connected to a source of alternating current that produces a constantly varying magnetic field around the coil. The varying magnetic field, in turn, produces an alternating current in the other coil.

This coil, called the secondary, is connected to a separate electric circuit.

The ratio of the number of turns in the primary coil to the number of turns in the secondary coil—the turns ratio—determines the ratio of the voltages in the two coils. For example, if there is one turn in the primary and ten turns in the secondary coil, the voltage in the secondary coil will be 10 times that in the primary. Such a transformer is called a step-up transformer. If there are ten turns in the primary coil and one turn in the secondary the voltage in the secondary will be one-tenth that in the primary. This kind of transformer is called a step-down transformer. The ratio of the electric current strength, or amperage, in the two coils is in inverse proportion to the ratio of the voltages; thus the electrical power (voltage multiplied by amperage) is the same in both coils. The impedance (resistance to the flow of an alternating current) of the primary coil depends on the impedance of the secondary circuit and the turn’s ratio.

With the proper turn’s ratio, the transformer can, in effect, match the impedances of the two circuits. Matched impedances are important in stereo systems and other electronic systems because they permit the maximum amount of electric power to be delivered from one component to another. In an autotransformer, there is only one coil and both circuits are connected to it. They are connected at different points, so that one circuit contains a larger portion of the coil (that is, has more turns) than the other. The name itself offers a simple definition. Electrical transformers are used to transform electrical energy. How electrical transformers do so is by altering voltage, generally from high to low. Voltage is simply the measurement of electrons, how many or how strong, in the flow. Electricity can then be transported more easily and efficiently over long distances. While power line electrical transformers are commonly recognized, there are other various types and sizes as well.

They range from huge, multi-ton units like those at power plants, to intermediate, such as the type used on electric poles, and others can be quite small. Those used in equipment or appliances in your home or place of business are smaller electrical transformers and there are also tiny ones used in items like microphones and other electronics. Probably the most common and perhaps the most necessary use of various electrical transformers is the transportation of electricity from power plants to homes and businesses.

Because power often has to travel long distances, it is transformed first into a more manageable state. It is then transformed again and again, or “stepped down,” repeatedly as it gets closer to its destination. When the power leaves the plant, it is usually of high voltage. When it reaches the substation the voltage is lowered. When it reaches a smaller transformer, the type found on top of electric poles, it is stepped down again. It is a continuous process, which repeats until the power is at a usable level.

BACKGROUND OF STUDY:

Electrical transformers are used to “transform” voltage from one level to another, usually from a higher voltage to a lower voltage. They do this by applying the principle of magnetic induction between coils to convert voltage and/or current levels. In this way, electrical transformers are a passive device which transforms alternating current (otherwise known as “AC”) electric energy from one circuit into another through electromagnetic induction. An electrical transformer normally consists of a ferromagnetic core and two or more coils called “windings”. A changing current in the primary winding creates an alternating magnetic field in the core.

In turn, the core multiplies this field and couples the most of the flux through the secondary transformer windings. This in turn induces alternating voltage (or emf) in each of the secondary coils. A transformer is an electrical device that takes electricity of one voltage and changes it into another voltage. You’ll see transformers at the top of utility poles and even changing the voltage in a toy train set. Basically, a transformer changes electricity from high to low voltage using two properties of electricity. In an electric circuit, there is magnetism around it. Second, whenever a magnetic field changes (by moving or by changing strength) a voltage is made. Voltage is the measure of the electric force or “pressure” that “pushes” electrons around a circuit.

Electrical transformers can be configured as either a single-phase or a three-phase configuration. There are several important specifications to specify when searching for electrical transformers. These include: maximum secondary voltage rating, maximum secondary current rating, maximum power rating, and output type. An electrical transformer may provide more than one secondary voltage value. The Rated Power is the sum of the VA (Volts x Amps) for all of the secondary windings. Output choices include AC or DC. For Alternating Current waveform output, voltage the values are typically given in RMS values. Consult manufacturer for waveform options.

For direct current secondary voltage output, consult manufacturer for type of rectification. Cores can be constructed as either a toroidal or laminated. Toroidal units typically have copper wire wrapped around a cylindrical core so the magnetic flux, which occurs within the coil, doesn’t leak out, the coil efficiency is good, and the magnetic flux has little influence on other components. Laminated refers to the laminated-steel cores. These steel laminations are insulated with a nonconducting material, such as varnish, and then formed into a core that reduces electrical losses. There are many types. These include autotransformer, control, current, distribution, general-purpose, instrument, isolation, potential (voltage), power, step-up, and step-down. Mountings include chassis mount, dish or disk mount, enclosure or free standing, h frame, and PCB mount.

STATEMENT OF THE PROBLEM:

→ How to Identify Electric Transformers?

→ How Does Electric Transformers Work?

→ Why Does Electric Transformers explode?

SIGNIFICANCE OF THE STUDY:

Electrical Engineering Students- They will find the material needed to advance toward the level of professional. They can use to obtain a deeper understanding of many topics.

Electrical Engineers- They deeply involve with the overall subject matter of this book may smugly grin with the self-satisfying attitude of “I know all that!” This person must recognize that there are many transformer topics. There is always room to learn.

Electronics Engineering Students- To train specialists for transformers needed in industry, higher education and research.

Electronics Engineers- To immerse in one or a few very narrow specialties within the field that they also may benefit greatly from their knowledge imparted in the peripheral specialties.

Electrical Options- Ensure a high level of applied, scientific and instructional work in the transformer field through collaboration.

Researchers- They will become knowledgeable about the selected topic.

SCOPE AND LIMITATION:

This standard establishes firm capacity and short term overload ratings for distribution substation electric transformers based on temperature rise of the transformer core and coils. The electric transformers consider a limitation imposes by substation ancillary equipment such as tap changers, bushings, breakers, etc. Power capacity has already been observed, transformers must be well designed in order to achieve acceptable power coupling, tight voltage regulation, and low exciting current distortion. Also, transformers must be designed to carry the expected values of primary and secondary winding current without any trouble. This means the winding conductors must be made of the proper gauge wire to avoid any heating problems. An ideal transformer would have perfect coupling (no leakage inductance), perfect voltage regulation, perfectly sinusoidal exciting current, no hysteresis or eddy current losses, and wire thick enough to handle any amount of current.

Unfortunately, the ideal transformer would have to be infinitely large and heavy to meet these design goals. Thus, in the business of practical transformer design, compromises must be made. Additionally, winding conductor insulation is a concern where high voltages are encountered, as they often are in step-up and step-down power distribution transformers. Not only do the windings have to be well insulated from the iron core, but each winding has to be sufficiently insulated from the other in order to maintain electrical isolation between windings. Respecting these limitations, transformers are rated for certain levels of primary and secondary winding voltage and current, though the current rating is usually derived from a volt-amp (VA) rating assigned to the transformer. For example, take a step-down transformer with a primary voltage rating of 120 volts, a secondary voltage rating of 48 volts, and a VA rating of 1 kVA (1000 VA). The maximum winding currents can be determined as such:

Sometimes windings will bear current ratings in amps, but this is typically seen on small transformers. Large transformers are almost always rated in terms of winding voltage and VA or kVA. When energy losses transformers transfer power, they do so with a minimum of loss. As it was stated earlier, modern power transformer designs typically exceed 95% efficiency. It is good to know where some of this lost power goes, however, and what causes it to be lost. There is, of course, power lost due to resistance of the wire windings. Unless superconducting wires are used, there will always be power dissipated in the form of heat through the resistance of current-carrying conductors. Because transformers require such long lengths of wire, this loss can be a significant factor. Increasing the gauge of the winding wire is one way to minimize this loss, but only with substantial increases in cost, size, and weight. Resistive losses aside, the bulk of transformer power loss is due to magnetic effects in the core.

Perhaps the most significant of these “core losses” is eddy-current loss, which is resistive power dissipation due to the passage of induced currents through the iron of the core. Because iron is a conductor of electricity as well as being an excellent “conductor” of magnetic flux, there will be currents induced in the iron just as there are currents induced in the secondary windings from the alternating magnetic field. These induced currents — as described by the perpendicularity clause of Faraday’s Law — tend to circulate through the cross-section of the core perpendicularly to the primary winding turns. Their circular motion gives them their unusual name: like eddies in a stream of water that circulates rather than move in straight lines. Iron is a fair conductor of electricity, but not as good as the copper or aluminum from which wire windings are typically made. Consequently, these “eddy currents” must overcome significant electrical resistance as they circulate through the core.

In overcoming the resistance offered by the iron, they dissipate power in the form of heat. Hence, we have a source of inefficiency in the transformer that is difficult to eliminate. This phenomenon is so pronounced that it is often exploited as a means of heating ferrous (iron-containing) materials. The photograph of shows an “induction heating” unit raising the temperature of a large pipe section. Loops of wire covered by high-temperature insulation encircle the pipe’s circumference, inducing eddy currents within the pipe wall by electromagnetic induction. In order to maximize the eddy current effect, high-frequency alternating current is used rather than power line frequency (60 Hz). The box units at the right of the picture produce the high-frequency AC and control the amount of current in the wires to stabilize the pipe temperature at a pre-determined “set-point.”

Induction heating: Primary insulated winding induces current into loss iron pipe (secondary). DEFINITION OF TERMS: Alternating Current (AC)- An electrical current flow of continuously changing polarity, which rises to a maximum voltage in one direction, decreases to zero and then sinks to the maximum voltage in the other direction before changing polarity once again. This pattern is referred to as a sinusoidal wave and the number of cycles per second is equal to the frequency, which is measured in “Hertz”. Ambient Temperature- The normal surrounding temperature of the environment in which a transformer will operate. Auto Transformer- A transformer used to step voltage up or down. The primary and secondary windings share common turns and thus provide no electrical isolation.

Air cooled Transformer- A transformer which uses air as the cooling medium. This may be a forced air with the use of fans. Arc voltage- The amount of voltage present between electrodes of different potential or between an electrode and ground. The magnitude is determined by the distance between electrodes and the dielectric constant of the medium surrounding them. Breakdown voltage- The voltage at which an electrical breakdown occurs. It is also known as breakdown potential, sparking potential or sparking voltage. Core- The ferrous center part of a transformer or inductor used to increase the strength of the magnetic field. It carries the flux and forms the magnetic coupling between primary and secondary Core Saturation- Condition that occurs when an inductor or transformer core has reached maximum magnetic strength. Current Transformer (CT)- A transformer used in instrumentation to assist in measuring current.

It utilizes the strength of the magnetic field around the conductor to form an induced current that can then be applied across a resistance to form a proportional voltage. Compensated Transformer- A transformer with a turn’s ratio which provides a higher than rated voltage at no load, and, rated voltage at rated load. Core Loss- Core loss is also known as iron loss. Core loss is a form of energy loss that occurs in electrical transformers and other inductors. Core losses do not include the losses due to resistance in the conductors of the windings, which is often termed copper loss. It does not vary with load and hence also called constant losses. It mainly consists of eddy current and hysteresis losses. Double conversion- A UPS design in which the primary power path consists of a rectifier and inverter. Dropout voltage- The voltage at which a device fails to operate properly or safely. Computer systems will reboot, reset, or lose data. Delta- Delta is a three phase connection where the ends of each phase winding connection in series to form a closed loop with each phase 120 electrical degrees from the other. Delta-Delta- The connection between a delta source and a delta load. Delta-Wye- The connection between a delta source and a wye load.

Duty Cycle- The percentage of time a transformer will be supplying the Full Rated Power to the load. Percentage of time a unit is expected to perform at Full Rated power versus time spent in idle can significantly affect the physical size of a transformer. Electrostatic Shield- A grounded conductor sheet which provides a ground shield between primary and secondary windings to decrease or eliminate line to line or line to ground noise. It is also known as Faraday Shield. Effective Voltage or current- The amount of power being delivered to a DC circuit load can be calculated easily by dividing the load resistance into the applied DC voltage squared. Eddy Currents- It is induced into a metal when magnetic lines of force move across it. Efficiency- Ratio of its power output to its total power input. Excitation Current- Current required magnetizing a core..

Electrostatic Shielding- Placed between windings (usually the primary and secondary) to provide maximum isolation. Additional Electrostatic Shields can be placed between secondary windings as required. Shielding is normally connected to the transformer’s ground. Exciting Current- The current drawn by a transformer at nominal input voltage in its unloaded (open-circuit) condition. Frequency- It means the number of times an AC voltage will change from positive to negative and vice versa within a precise time, usually expressed in cycles per second and identified as Hz as in 60 Hz. Ferroresonant Transformer- A voltage-regulating transformer that depends on core saturation and output capacitance. Filter- A selective network of resistor, inductors, or capacitors which offers comparatively little opposition to certain frequencies or direct current, while blocking or attenuating other frequencies. Flux- The lines of forces of a magnetic field.

Forced Air- A method of temperature regulation that involves air from an external environment being forcibly exchanged with a transformer’s enclosed environment. Generator- A device that converts mechanical energy into electrical energy by magnetic induction. Ground- A conducting path, whether intended or unintended, between an electric circuit or equipment and the earth or some other conductor. Grounded- Connected to the earth or some other conductor.

Ground Fault- Any undesirable current flow from a current carrying conductor to ground. Hydroelectric- Electricity produced by turbines that are turned by water flow. Hertz (Hz)- Cycles per second.

Isolating Transformer- Transformer in which input windings are connected to the line and are completely isolated from those connected to the load. Insulation- Material with high electrical resistance.

Insulator- Device used for supporting or separating electrical conductors. Instrument Transformer- A transformer designed to transform the conditions of current or voltage and phase position in the primary with a specified accuracy of the secondary circuit. Inductor- A coiled conductor that opposes change in current. Inverter- A device used to change DC into AC power.

Network Transformer- Transformer which is electrically and mechanically connected to and coordinated in design with switch-gear or motor control assemblies for use on a utility network power system. Power Factor- Watts divided by volt amps, kW divided by kVA. Power factor: leading and lagging of voltage versus current caused by inductive or capacitive loads, and harmonic power factor: from nonlinear current. Primary winding- The coil winding that is directly connected to the input supply. Peak voltage- Highest voltage measured during an event. Or the maximum voltage obtained from an oscillating voltage wave. With an AC source, this occurs twice and lasts for only a fraction of the cycle. Direct current voltage is considered peak voltage at all times. Rated Power- The total output power available from all secondary windings, expressed in Volt-amperes (VA) or Kilovolt amperes (kVA). Reactance- Opposition to changes in flow of alternating current. Capacitive reactance is opposition in change from a capacitor, and inductive reactance is the opposition in change from a coil or other inductor.

Rectifier- An electrical device used to change AC power into DC power. Regulation- The percentage difference between a secondary winding’s output voltage when operating under no-load and open-circuit and full load conditions. Secondary Winding(s)- The coil winding(s) supplying the output voltage to the load(s). Short circuit- A low resistance connection, usually accidental, across part of a circuit, resulting in excessive current flow. Transformer Bank / Bank of transformers- Two or more single-phase transformers connected together to supply a three-phase load. Taps or Voltage Taps- Additional connections to winding allowing different voltages to be obtained from the same winding. Often used on the primary winding to allow the transformer to be used in different countries having different line voltages available. Transformer- An electrical device, which, by electromagnetic induction, regenerates AC power from one circuit into another. Transformers are also used to change voltage from one level to another. This is accomplished by the ratio of turns on the primary to turns on the secondary (turns ratio). |

Working Voltage- The voltage that a winding will operate at, but not necessarily the output voltage of the winding.Wye- A wye connection refers to a three-phase electrical supply where the source transformer has the conductors connected to the terminals in a physical arrangement resembling a Y. Each point of the Y represents the connection of a hot conductor. The angular displacement between each point of the Y is 120 degrees. The center point is the common return point for the neutral conductor.Watt- Unit of electrical power when the current in the circuit is one ampere and the voltage is one volt (for DC) and for AC, even the p.f. should be unity.Weather shield- When added to ventilated enclosures, allow indoor-rated units to be situated outdoors, changing the enclosure rating to NEMA 3R.

Book Report on Pigeons at Daybreak Essay

The story entitled “Pigeons at Daybreak” by Anita Desai of India is a representation of love and acceptance. Mr. Basu is the man who is unable to perform his task on his own because of the different illnesses that developed into his body. Otima, the wife of Mr. Basu has the selfless love towards him. She takes care of her husband despite of all the problems and complications that emerged in their situation. Otima used to read the newspaper for Mr.

Basu. Because Mr. Basu could not able to read the newspaper due to poor eyesight, Otima produced deeper patience and love for her husband.

            From the time when their house had no electricity due to electric problems, the two went to the terrace and decided to stay there until the electricity comes back but when the electricity went back, Mr. Basu refused to go back inside the house for it was the time of preparation of leaving. Mr. Basu accepted the fact that his life will soon vanish and become part of heaven.

The pigeons in the terrace where Mr. Basu died symbolize his spirit and his journey in the next life.

            The story is simple yet attackable. Its tragic situation brought life to the whole story. Then, with a swirl and flutter of feathers, a flock of pigeons hurtled upwards and spread out against the dome of the sky – opalescent, sunlit, like small pearls (Desai 228). This ending part of the story compressed the entire claim of the story. It means that the ending of the story signifies life as its wondrous creation but soon will end because every one of us will leave the world in beauty and a new journey will begin.

Reference

Desai, A. (date). Pigeons at Daybreak. pp.220-228