PRESENTATION BY:- Murtuza Ranapur-13BECEG096 Mukti Vyas-13BECEG094 Rutvi Patel-13BECEG081

1. FOR INTERACTIVE LEARNING:- • ACTIVE LEARNING ASSINGMENT:- • SUBJECT:- • EEE • SUBJECT:- • EEE • TOPIC:- • Current, Voltage, Power and Energy. • TOPIC:- • Current, Voltage, Power and Energy. • PRESENTATION BY:- • Murtuza Ranapur-13BECEG096 • Mukti Vyas-13BECEG094 • Rutvi Patel-13BECEG081 • Vaibhavi Khamar-13BECEG098 • PRESENTATION BY:- • Murtuza Ranapur-13BECEG096 • Mukti Vyas-13BECEG094 • Rutvi Patel-13BECEG081 • Vaibhavi Khamar-13BECEG098 • GUIDED BY:- • Sagar Aheire(ADHOC Assistant Proff.) • GUIDED BY:- • Sagar sir • BRANCH:- • Computer Engineering:2

2. ∂ ᴀ Ʊ ᶲ ℮ CURRENT VOLTAGE POWER ENERGY Ω ∞ ᴈ ∂ Ө ℰ Р ᶲ Р ℰ Ʊ Ω ᴀ ᴈ Ө ℮ ∞

3. CURRENT • Current(I) is a measure of how much charge(Q) is • flowing through a circuit at a particular moment. • Or its another definition is: • Electric current is the rate of charge flow past a • given point in an electric circuit, measured in • Coulombs/second which is named Amperes. In most • DC electric circuits, it can be assumed that the • resistance to current flow is a constant so that the • current in the circuit is related to voltage and • resistance by Ohm's law. The standard • Abbreviations for the units are 1 A = 1C/s. Q (ᴀ) I= ── t

4. DIRECTION OF CURRENT Conventional Current assumes that current flows out of the positive terminal, through the circuit and into the negative terminal of the source Electron Flow is what actually happens and electrons flow out of the negative terminal, through the circuit and into the positive terminal of the source In fact, it makes no difference which way current is flowing as long as it is used consistently. The direction of current flow does not affect what the current does.

5. TYPES OF CURRENT • Alternating Current(AC):- • In AC, electrons keep switching directions, sometimes going "forwards" and then going "backwards.“ • Safe to transfer over longer city distances and can provide more power. • The frequency of alternating current is 50Hz or 60Hz depending upon the country. • It reverses its direction while flowing in a circuit. • It is the current of magnitude varying with time. • Power factor Lies between 0 & 1. • It’s types are Sinusoidal, Trapezoidal, Triangular, Square. • Direct Current(DC):- • In DC, the electrons flow steadily in a single direction, or "forward. • Voltage of DC cannot travel very far until it begins to lose energy. • The frequency of direct current is zero. • It flows in one direction in the circuit. • It is the current of constant magnitude. • Power Factor it is always 1. • It’s types are Pure and pulsating. DC V AC t

6. AMMETER An ammeter is a measuring instrument used to measure the electric current in a circuit. Electric currents are measured in amperes (A), hence the name. Instruments used to measure smaller currents, in the milliampere or microampere range, are designated as milliammeters or microammeters.

7. DRIFTSPEED & NATURE OF FLOW OF CURRENT • Drift speed refers to the average distance traveled by a charge carrier per unit of time. • Like the speed of any object, the drift speed of an electron moving through a wire is the distance to time ratio. • The path of a typical electron through a wire could be described as a rather chaotic, zigzag path characterized by collisions with fixed atoms. • Each collision results in a change in direction of the electron. • Yet because of collisions with atoms in the solid network of the metal conductor, there are two steps backwards for every three steps forward.

8. With an electric potential established across the two ends of the circuit, the electron continues to migrate forward. • Progress is always made towards the positive terminal. • Yet the overall affect of the countless collisions and the high between-collision speeds is that the overall drift speed of an electron in a circuit is abnormally low. • A typical drift speed might be 1 meter per hour. That is slow! • If it travels so slow then one might question how can flashlight lights immediately after switching on the power supply? • Once the switch is turned to on, the circuit is closed and there is an electric potential difference is established across the two ends of the external circuit. • The electric field signal travels at nearly the speed of light to all mobile electrons within the circuit, ordering them to begin marching. • As the signal is received, the electrons begin moving along a zigzag path in their usual direction.

9. The electrons that light the bulb in a flashlight do not have to first travel from the switch through 10 cm of wire to the filament. • Rather, the electrons that light the bulb immediately after the switch is turned to on are the electrons that are present in the filament itself. • As the switch is flipped, all mobile electrons everywhere begin marching; and it is the mobile electrons present in the filament whose motion are immediately responsible for the lighting of its bulb. • As those electrons leave the filament, new electrons enter and become the ones that are responsible for lighting the bulb.

10. KRICHHOFF’S CURRENT LAW • This law is also called Kirchhoff's first law, Kirchhoff's point rule, or Kirchhoff's junction rule (or nodal rule). • The principle of conservation of electric charge implies that: • At any node (junction) in an electrical circuit, the sum of currents flowing into that node is equal to the sum of currents flowing out of that node, or: The algebraic sum of currents in a network of conductors meeting at a point is zero. • Recalling that current is a signed (positive or negative) quantity reflecting direction towards or away from a node, this principle can be stated as: • The current entering any junction is • equal to the current leaving that junction. • i2+ i3 = i1 + i4

11. ITS LIMITATIONS • KCL, in its usual form, is dependent on the assumption that current flows only in conductors, and that whenever current flows into one end of a conductor it immediately flows out the other end. • This is not a safe assumption for AC circuits. • In other words, KCL is valid only if the total electric charge , Q, remains constant in the region being considered. • When investigating a finite region, however, it is possible that the charge density within the region may change. • Since charge is conserved, this can only come about by a flow of charge across the region boundary. • This flow represents a net current, and KCL is violated.

12. VOLTAGE • Voltage attempts to make a current flow, and current will flow if the circuit is complete. • Voltage is sometimes described as the 'push' or 'force' of the electricity, it isn't really a force but this may help you to imagine what is happening. • It is possible to have voltage without current, but current cannot flow without voltage. • Voltage is a measure of the energy carried by the charge. • The proper name for voltage is potential difference or p.d. for short. • Voltage is supplied by the battery (or power supply). • Voltage is measured in volts, V. • Voltage is measured with a voltmeter, connected in parallel. • The symbol V is used for voltage in equations. The switch is closed making a complete circuit so current can flow. The switch is open so the circuit is broken and current cannot flow. Without the cell there is no source of voltage so current cannot flow.

13. VOLTMETER A voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; digital voltmeters give a numerical display of voltage by use of an analog to digital converter.

14. ELECTROMOTIVE FORCE • Electromotive force, also called emf (denoted and measured in volts), is the voltage developed by any source of electrical energy such as a battery or dynamo. • The word "force" in this case is not used to mean mechanical force, measured in newton's, but a potential, or energy per unit of charge, measured in volts. • The source of emf can be thought of as a kind of charge pump that acts to move positive charge from a point of low potential through its interior to a point of high potential. • By chemical, mechanical or other means, the source of emf performs work dW on that charge to move it to the high potential terminal. • The emf ℰ of the source is defined as the work dW done per charge dq: ℰ = dW/dq.

15. KRICHHOFF’S VOLTAGE LAW • This law is also called Kirchhoff's second law, Kirchhoff's loop (or mesh) rule, and Kirchhoff's second rule. • Similarly to KCL, it can be stated as: • This law is based on one of the Maxwell equations, namely the Maxwell-Faraday law of induction, which states that the voltage drop around any closed loop is equal to the rate-of-change of the flux threading the loop. • The amount of flux depends on the area of the loop and on the magnetic field strength. • KVL states the loop voltage is zero.

16. The Maxwell equations tell us that the loop voltage will be small if the area of the loop is small, the magnetic field is weak, and/or the magnetic field is slowly changing. • The sum of all the voltages around the loop is equal to zero. v1 + v2 + v3 - v4 = 0

17. ITS LIMITATION • This is a simplification of Faraday's law of induction for the special case where there is no fluctuating magnetic field linking the closed loop. • Therefore, it practically suffices for explaining circuits containing only resistors and capacitors. • In the presence of a changing magnetic field the electric field is not conservative and it cannot therefore define a pure scalar potential—the line integral of the electric field around the circuit is not zero. • In order to "fix" Kirchhoff's voltage law for circuits containing inductors, an effective potential drop, or electromotive force (emf), is associated with each inductance of the circuit, exactly equal to the amount by which the line integral of the electric field is not zero by Faraday's law of induction.

18. POWER • Electric power is the rate at which electric energy is transferred by an electric circuit. • The SI unit of Power is the watt, one joule per second. • Electric power is usually produced by electric generators, but can also be supplied by chemical sources such as electric batteries. • Electric power, like mechanical power, is the rate of doing work, measured in watts, and represented by the letter P. where • Q is electric charge in coulombs • t is time in seconds • I is electric current in amperes • V is electric potential or voltage in volts

19. A C P O W E R • In Alternating Current circuits, energy storage elements such as inductance and capacitance may result in periodic reversals of the direction of energy flow. • The portion of power flow that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as real power. • That portion of power flow due to stored energy, that returns to the source in each cycle, is known as reactive power. The real power P in watts consumed by a device is given by • Vp is the peak voltage in volts • Ip is the peak current in amperes • Vrms is the root-mean-square voltage in volts • Irms is the root-mean-square current in amperes • θ is the phase angle between the current and voltage sine waves Relation between Apparent Power, Reactive Power & Real Power

20. POTENTIAL ENERGY • Electric potential energy, or electrostatic potential energy, is a potential energy (measured in joules) that results from conservative Coulomb forces and is associated with the configuration of a particular set of point charges within a defined system. • An object may have electric potential energy by virtue of two key elements: its own electric charge and its relative position to other electrically charged objects. • The term "electric potential energy" is used to describe the potential energy in systems with time-variant electric fields. • while the term "electrostatic potential energy" is used to describe the potential energy in systems with time-invariant electric fields.

21. The electrostatic potential energy, UE, of one point charge q at position r in the presence of an electric field E is defined as the negative of the work W done by the electrostatic force to bring it from the reference position rref to that position r. • It can also be defined as: • The electrostatic potential energy, UE, of one point charge q at position r in the presence of an electric potential is defined as the product of the charge and the electric potential. • The electrostatic potential energy, UE, of one point charge q at position r in the presence of a point charge Q, taking an infinite separation between the charges as the reference position, is: • where is Coulomb's constant, r is the distance between the point charges q & Q, and q & Q.

22. Energy stored in an electrostatic field distribution. • The energy density, or energy per unit volume, ,of the electrostatic field of a continuous charge distribution is: • Energy in electronic elements: • Some elements in a circuit can convert energy from one form to another. For example, a resistor converts electrical energy to heat, this is known as the Joule effect. A capacitor stores it in its electric field. The total electric potential energy stored in a capacitor is given by • where C is the capacitance, V is the electric potential difference, and Q the charge stored in the capacitor.

23. THANK YOU