The goal of the “Resistance and Electric Circuit” Lab was to determine the resistivity of a conducting wire given two known resistors. The main property of resistivity is that it represents how easily electrons can flow through a material. A Galvanometer is used to measure the current of the circuit and the Wheatstone Bridge is used to measure the resistances and determine the unknown resistance. This experiment also relates Ohm’s Law to determine the resistivity using the resistance of the wire, length of the wire, and cross sectional area. In order to relate a measured resistance as a function of length and obtain the value for an unknown resistor, a Wheatstone Bridge must be attached to a dc power supply, and a galvanometer. In order to determine the correct value for the known resistance, the galvanometer must read zero. Second, to relate the resistance to a specific length a micrometer is used in connection to a variable resistance box. Use six difference lengths on the micrometer, we chose intervals of 10, starting at 10 centimeters and ending at 60 centimeters. For the first set of data points, drag the micrometer tab to rest on 10 centimeters (have the same person press down on the wire for every data point using the same force because a change in force on the wire could vary the results). Then, using the variable resistor box, increase the resistance of the box until the galvanometer reads a value of zero. When the galvanometer reads zero the resistance shown on the variable resistance box is the unknown resistance relating to the specific length on the wire. Repeat these steps for five more values on the micrometer. After conducting, the experiment using a known R1 of 100Ω and R2 of 10Ω several data points were obtained and a line graph was formatted to relate the Resistance (R) and Length (L): Length (m)| R3 (Ω)| R3/10= R (Ω)|

...Engineering EE 241- ElectricCircuits I 3(3-0-0)
Required Course: Three 1-hour lectures per week
Semester 1, 2013-2014
•Course Instructor and/or Coordinator. •Course Description (catalog):
Linear circuit analysis and design course. Topics include fundamental topics of charge, current, voltage and power; passive circuit elements; mesh and nodal analysis, Thevenin's and Norton's theorems, source transformation; transient analysis in time. There are 3 lectures per week, each lasts for 1 hour.
Prerequisite(s):
Co-requisite(s): Math 240 Textbooks:
•ElectricCircuits, 9th Edition, Nilsson/Riedel, Pearson Publishing Company, 2011, ISBN-10: 0-13-705051-8
•Handouts distributed by the instructor. References: •Foundation of ElectricCircuits, 1st Edition, Cogdel, Prentice Hall, 1999, ISBN-10: 0139077421 • Circuit Analysis, 1st Edition, Jackson, Prentice Hall, 2006, ISBN-10: 0130932248 Instructor Time and Place Office Office Hours Telephone: Email: Dr. Mounir Bouzguenda
Sun/Tue/Thu 9:30 – 10:20 am, Room 1023B
Room :1051, College of Engineering, Bldg 31
Sun/Tue/Thu 10:30 – 11:30 am
9064 mbuzganda@kfu.edu.sa
Quizzes Homework Assignments Project + presentation Exam 1 Exam 2 Final Exam
10% 10% 20% 20% 20% 20%
1
Specific Outcomes of Instruction (Course Learning Outcomes):•
After completing the course, the student will be able to:...

...Batteries, Resistance and Current
“Battery-Resistor”:
Check “show battery” and “show cores”, watch what happens, adjust some variables
1. Why do electrons (blue dots) move? Draw a diagram of the battery, label the flow of electrons. The flow of current (+) is opposite; draw this and note if toward or away from + terminal of the battery.
The electrons move because of the battery voltage. The current flows in the opposing direction of the electrons and the electrons flow towards the positive side.
2. What does the Ammeter (on the left) measure? How is this shown in the sim?
The ammeter measures amperes on the bottom left of the simulation.
3. What role do the “green dots” in the resistor play in the sim? What do you think they represent? What does this tell you about the effect of resistors in a circuit?
The green dots control the flow of electrons. The green dots put resistance on the flow of electrons. When the green dots (resistance) is turned down the electrons move quicker allowing for the battery to get hotter.
4. Increase the resistance (# green dots). What affect does this have on temperature? WHY?
It makes the temperature decrease, because the green dots have an increased resistance on the electrons it allows the electrons to move slower, in turn in a lesser quantity per second.
5. When the circuit gets hotter, what affect does...

...What happens to resistance of a conductor when its area of cross-section is increased?
Ans.
Resistance decreases
Question 2
The charge possessed by an electron is 1.6x10-19 coulombs. Find the number of electrons that will flow per second to constitute a current of 1 ampere.
Ans.
Question 3
Name the instrument used to measure electric current in a circuit.
Ans.
Ammeter
Question 4
In the following table the values of current I flowing in a given resistor for the corresponding values of potential difference V across the resistor are shown :
I(amperes) | 0.5 | 1.0 | 2.0 | 3.0 | 4.0 |
V(Volts) | 1.6 | 3.4 | 6.7 | 10.2 | 13.2 |
Plot a graph between V and I and use this graph to find the value of current when potential difference across the resistor is 5V.
Ans.
Finding the current corresponding to 5 V potential difference (from graph) =1.5 A (approx.)
Question 5
(a) What does the following circuit symbols represent?
(i) (ii)
(b) The potential difference between the terminals of an electric heater is 60 V when it draws a current of 4 A from the source. Find the resistance of heater when in use.
Ans.
(a) (i) Wires not connected
(ii) Variable resistor/rheostat
Question 6
Mention any two factors on which the resistance of a cylindrical conductor depends.
Ans.
Its length, its cross sectional area, nature of...

...have to check the resistance from the graph see what is plotted along the x and y axis. Reason why alloys are used to make elements of electric irons and heaters is not because they are insulators.
2.
Units
3. 4.
Formula Graphs
5.
Resistivity
6.
Change in resistance
If a wire is folded(doubled on it) and made half its length, then the resistance does not become half.
7.
Resistors in series
Is the current or the voltage same in resistors in series.
How to avoid The direction of current is opposite to the direction of movement of electrons. In a circuit current always flows from positive to negative terminal and you need to put arrows in this direction. The symbol for ampere is A and not amp. If you wish you can use “ampere” instead of “A”. Make sure you memorize this formula correctly. If V is plotted along y axis and I is plotted along x axis then the slope of the graph gives R. If V is plotted along x axis with I along the y axis then the slope of the graph gives 1/R. Had the alloys been insulators then current would not flow at all. We want current to flow in these devices as well as heat up the wire, so we cannot use a very good conductor like copper, aluminium etc. and the best choice is to use an alloy that has a high resistivity. Remember that the area of cross-section also becomes double, so the new resistance is ¼ the old...

...To design a simple electrical circuit for Doctor's Surgery to let people know when to enter and also to research and learn more about parallel and series circuits.
Introduction
I am going to design an electriccircuit for a Doctor's surgery.
There are two types of circuit's Parallel circuit, and Series circuit.
First I am going to explain what a circuit is and what the differences they have are.
An electric current is a flow of charge. The charges are given energy and made of flow using a cell or a battery. Charges can flow easily through connecting wire. The cell, wires, lamp and a switch, all these components are connected together and make a loop called a circuit.
Current will only flow through a component if there is a voltage across that component.
Voltage is the driving force that pushes the current round.
Parallel Circuit
In a parallel circuit you can add more components without the need for more voltage.
In a parallel circuit a failure of one component does not lead to the failure of the complete circuit, this is because a parallel circuit has more than on loop and all have to fail in more than one place before the other components fail.
Series Circuit
In series circuit (which I will be designing for the surgery) is a loop of wire...

...the comb become charged by rubbing. This stationary electric charge is described as static electricity.
Activity 1.
Rub a plastic sheet with flannel and then hold the plastic sheet near Styrofoam bits. What do you observe?
From the observations made, you can conclude that rubbing produces static electricity on the rubbed objects. The two objects, when rubbed against each other, become electrified. We can described them as being charged.
Activity 2.
Prepare a simple electroscope, using the following materials: iron stand, silk thread, small Styrofoam ball covered with aluminum foil.
The electroscope is a simple instrument that can help detect the presence of static electricity. If a glass rod were rubbed with a piece of cloth then placed near the ball, the ball will be attracted to the rod. After a few seconds of contact with the rod, the ball will be repelled. Why? If a plastic rod were rubbed with flannel or wool, and the rod placed closed to the ball, the same result will be observed. Both the silk and woolen pieces of cloth also show signs of having been electrified when placed closed to the electroscope.
The observations made in activity 2 indicate that a body consist of charge particles and that there are two kinds of charges.
Benjamin Franklin (1706-1790) described this charges as positive and negative. He called the electrical condition that the glass acquires when it has been rubbed with silk as positive electric charge and the...

...a p t e r
2
Resistance
No pain, no palm; no thorns, no throne; no gall, no glory; no cross,
no crown.
—William Penn
Historical Proﬁles
Georg Simon Ohm (1787–1854), a German physicist, in 1826
experimentally determined the most basic law relating voltage and current for a resistor. Ohm’s work was initially denied by critics.
Born of humble beginnings in Erlangen, Bavaria, Ohm threw himself into electrical research. Ohm’s major interest was current electricity, which had recently been advanced by Alessandro Volta’s invention
of the battery. Using the results of his experiments, Ohm was able to
deﬁne the fundamental relationship among voltage, current, and resistance. This resulted in his famous law—Ohm’s law—which will be covered in this chapter. He was awarded the Copley Medal in 1841 by the
Royal Society of London. He was also given the Professor of Physics
chair in 1849 by the University of Munich. To honor him, the unit of
resistance is named the ohm.
Ernst Werner von Siemens (1816–1892) was a German electrical
engineer and industrialist who played an important role in the development of the telegraph.
Siemens was born at Lenthe in Hanover, Germany, the oldest of
four brothers—all of whom were distinguished engineers and industrialists. After attending grammar school at Lübeck, Siemens joined the
Prussian artillery at age 17 for the training in engineering that his father
could not afford. Looking at an...

...TO: 1201 Section-002 Instructor
FROM: Engineer Student
DATE: February 16, 2015
RE: Electrical Circuit Project Lab Report
The purpose of the Electrical Circuit project was to prepare students with the ability to work with mathematical and engineering calculations to design a breadboard. In order to create a breadboard with an accurate voltage drop between nodes, the resistor combinations and calculations need to be correct.
Calculating the voltage drop between nodes was done through the use of the five nodes provided in class. In order to correctly set up the breadboard, the calculations were used to determine which set of resistors needed to be matched together. Each color on the resistor represents the resistor’s value. The first and second bands represent the first two digits of the resistor value, the third band represents the multiplier, and the fourth band is the tolerance. After adding up the total resistor values, it is significant to match up the resistors to create a total of the calculated result of voltage drops between nodes. A schematic that illustrates my breadboard was done through Microsoft Visio and included in my Electrical Design Package.
The breadboard was tested in class through the use of a voltmeter and a battery. The outcome of this project provides an understanding that the calculations play a significant role in the accuracy of the overall result of success. If the calculations were accurate, the result will be...

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