Electric cells convert chemical energy into electrical energy to produce electricity. Multiple cells connected together form a battery. Batteries produce a potential difference across their terminals through chemical reactions, providing energy to move electrons through an external circuit. The electromotive force (emf) of a battery is the voltage when no current flows, while internal resistance causes voltage to drop under load. Batteries can be connected in series, where the total emf is the sum of individual cells and current is the same through each, or in parallel, where the total current is the sum of individual cells and voltage is the same across each.
The apparatus used for switching, controlling & protecting the electrical circuits & equipments are known as switchgear.
The switchgear equipments is essentially used with switching & interrupting currents either under normal or abnormal operating condition.
It consists of devices such as switches, fuses, circuit breakers, relays etc.
Basically every electric circuit needs a switching device & a protecting device.
This ppt describes about,
introduction of fuses, construction, Important terms, advantages and disadvantages, desirable characteristics of fuse element, Current time characteristics, Fuse types - Low voltages fuses and High voltage fuses, Semi enclosed rewirable fuse, HRC cartridge fuses - parts, operation, pros and cons, High voltage fuses and its types, selection of fuses, discrimination
This is a small ppt made by me to describe about the basics of Insulators in HV , EHV transmission lines.Students who want to go through the basics for clearing the fundamentals they can go through this ppt. Thank you.
The apparatus used for switching, controlling & protecting the electrical circuits & equipments are known as switchgear.
The switchgear equipments is essentially used with switching & interrupting currents either under normal or abnormal operating condition.
It consists of devices such as switches, fuses, circuit breakers, relays etc.
Basically every electric circuit needs a switching device & a protecting device.
This ppt describes about,
introduction of fuses, construction, Important terms, advantages and disadvantages, desirable characteristics of fuse element, Current time characteristics, Fuse types - Low voltages fuses and High voltage fuses, Semi enclosed rewirable fuse, HRC cartridge fuses - parts, operation, pros and cons, High voltage fuses and its types, selection of fuses, discrimination
This is a small ppt made by me to describe about the basics of Insulators in HV , EHV transmission lines.Students who want to go through the basics for clearing the fundamentals they can go through this ppt. Thank you.
The presentation explain principal, working and construction and application of Potentiometer it is useful for senior secondary students of Indian school
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
2. • An electric cell converts chemical energy into
electrical energy to produce electricity.
• It contains two electrodes immersed in an
electrolyte
• Several electric cells connected together form a
battery.
• When a cell or battery is connected to a circuit,
electrons flow from the negative terminal to the
positive terminal through the circuit.
• By using chemical reactions, a battery produces
potential difference across its terminals.
• This potential difference provides the energy to
move the electrons through the circuit
5. • If we connect copper and zinc rod in a lemon,
it acts as an electric cell. The citric acid in the
lemon acts as an electrolyte. The potential can
be measured using a multimeter.
6. Electromotive force and internal
resistance
• A battery or cell is called a source of
electromotive force (emf).
• The term ‘electromotive force’ is a misnomer
since it does not really refer to a force but
describes a potential difference in volts.
• The emf of a battery or cell is the voltage
provided by the battery when no current flows
in the external circuit.
7. Measuring the emf of a cell
• Electromotive force determines the amount of
work a battery or cell does to move a certain
amount of charge around the circuit.
• It is denoted by the symbol ξ and to be
pronounced as ‘xi’.
• An ideal battery has zero internal resistance
and the potential difference (terminal voltage)
across the battery equals to its emf
8. • But a real battery is made of electrodes and
electrolyte, there is resistance to the flow of
charges within the battery.
• This resistance is called internal resistance r.
For a real battery, the terminal voltage is not
equal to the emf of the battery.
• A freshly prepared cell has low internal
resistance and it increases with ageing
12. • The emf of cell ξ is measured by connecting a
high resistance voltmeter across it without
connecting the external resistance R
• Since the voltmeter draws very little current
for deflection, the circuit may be considered
as open.
• Hence the voltmeter reading gives the emf of
the cell
13. • Then, external resistance R is included in the
circuit and current I is established in the
circuit.
• The potential difference across R is equal to
the potential difference across the cell (V)
• The potential drop across the resistor R is V=IR
• Due to internal resistance r of the cell, the
voltmeter reads a value V, which is less than
the emf of cell ξ
14. • It is because, certain amount of voltage (Ir)
has dropped across the internal resistance r.
Then V = ξ – Ir
• Ir = ξ – V
• Since ξ, V and R are known, internal resistance
r can be determined. We can also find the total
current that flows in the circuit.
15. • Due to this internal resistance, the power
delivered to the circuit is not equal to power
rating mentioned in the battery.
• For a battery of emf ξ, with an internal
resistance r, the power delivered to the circuit
of resistance R is given by
• P = Iξ = I (V + Ir)
• Here V is the voltage drop across the
resistance R and it is equal to IR.
• Therefore, P = I (IR +Ir)
16. • P = I2 R + I2 r
• Here I2 r is the power delivered to the internal
resistance and I2 R is the power delivered to
the electrical device .
• For a good battery, the internal resistance r is
very small, then I2 r << I2 R and almost entire
power is delivered to the resistance.
17.
18.
19. Cells in series
• Several cells can be connected to form a battery.
• In series connection, the negative terminal of
one cell is connected to the positive terminal of
the second cell, the negative terminal of second
cell is connected to the positive terminal of the
third cell and so on.
• The free positive terminal of the first cell and the
free negative terminal of the last cell become the
terminals of the battery.
20. • Suppose n cells, each of emf ξ volts and
internal resistance r ohms are connected in
series with an external resistance R
• The total emf of the battery = nξ
• The total resistance in the circuit = nr + R
• By Ohm’s law, the current in the circuit is
21. • Case (a) If r << R, then,
• where, I1 is the current due to a single cell
• Thus, if r is negligible when compared to R the
current supplied by the battery is n times that
supplied by a single cell.
22. • It is the current due to a single cell.
• That is, current due to the whole battery is the
same as that due to a single cell and hence
there is no advantage in connecting several
cells.
• Thus series connection of cells is
advantageous only when the effective internal
resistance of the cells is negligibly small
compared with R.
23.
24.
25. Cells in parallel
• In parallel connection all the positive
terminals of the cells are connected to one
point and all the negative terminals to a
second point.
• These two points form the positive and
negative terminals of the battery.
• Let n cells be connected in parallel between
the points A and B and a resistance R is
connected between the points A and B
26. • Let ξ be the emf and r the internal resistance
of each cell
27.
28.
29.
30. • The above equation implies that current due
to the whole battery is the same as that due
to a single cell.
• Hence it is advantageous to connect cells in
parallel when the external resistance is very
small compared to the internal resistance of
the cells.