1. Current Electricity

2. The movement of electric charge from one place to another. The movement of electric charge from one place to another.

3. Voltage Potential (Voltage)- Potential (Voltage)- IS THE ELECTRIC POTENTIAL PER CHARGE MOVING BETWEEN TERMINALS. THIS IS LIKE THE ELECTRIC PRESSURE PUSHING THE ELECTRONS. VOLTAGE DOES NOT MOVE, IT PUSHES THE ELECTRONS. http://faraday.physics.utoronto.ca/IYearLab/Intros /DCI/Flash/WaterAnalogy.html http://faraday.physics.utoronto.ca/IYearLab/Intros /DCI/Flash/WaterAnalogy.html

4. Low Voltage High Voltage

5. Low Voltage High Voltage

6. Voltage Potential (Voltage) cont’d- Potential (Voltage) cont’d- Measured in volts (V) Measured in volts (V) Measured using a voltmeter. Measured using a voltmeter.

7. Current Current- Current- The measure of the rate at which electric charges move past a given point in a circuit. Measures the amount of electricity passing a point. Measured in amperes (A) Measured using an: Ammeter- larger currents Galvanometer- smaller currents

8. High Current Low Current

9. High Current Low Current

10. Resistance Resistance Resistance The measure of an objects opposition to the passage of a steady electrical current The measure of an objects opposition to the passage of a steady electrical current Measured in ohm’s (Ω) Measured in ohm’s (Ω) Measured using an ohmmeter Measured using an ohmmeter

11. Low Resistance High Resistance Low Resistance

12. Ohm’s law Created by Georg Ohm (1789- 1854) Created by Georg Ohm (1789- 1854) “the potential difference between two points on a conductor is directly related to the electric current flowing through the conductor” “the potential difference between two points on a conductor is directly related to the electric current flowing through the conductor” Potential difference= Electric current x electrical resistance V = I x R

13. Example One What is the voltage drop across a tungsten filament in a 100-W light bulb? The resistance of the filament is 144 Ω and a current of 0.833 A is flowing through it. What is the voltage drop across a tungsten filament in a 100-W light bulb? The resistance of the filament is 144 Ω and a current of 0.833 A is flowing through it.

14. Example Two An electric toaster is connected to a 120-V outlet in the kitchen. If the heating element in the toaster has a resistance of 14 Ω, calculate the current flowing through it. An electric toaster is connected to a 120-V outlet in the kitchen. If the heating element in the toaster has a resistance of 14 Ω, calculate the current flowing through it.

15. Problem solving ? Textbook (10-10)

16. Electrical circuits Electrical circuit- Electrical circuit- Controlled path of flowing electricity in a complete circle Controlled path of flowing electricity in a complete circle Contain 4 parts Contain 4 parts 1. Source- Where electricity comes from. 2. Load- Where the electrical energy is transferred. 3. Control- What starts and stops the electricity. 4. Connectors- The path where the electricity runs.

17. SourceControl Load Connector

18. Electrical circuit- Source Cells- Converts chemical energy into electrical energy. Cells- Converts chemical energy into electrical energy. Batteries- combination of 2 or more cells Batteries- combination of 2 or more cells Generators-a device that converts movement into electrical energy Generators-a device that converts movement into electrical energy Photoelectric cells- a cell that converts light directly into electrical energy Photoelectric cells- a cell that converts light directly into electrical energy

19. CellBattery GeneratorPhotoelectric Cell

20. Electrical circuit- Source cont’d Cells Primary cells- Disposable cells Primary cells- Disposable cells Secondary cell- reusable cells Secondary cell- reusable cells All cells contain: Electrodes- Metal plates that are placed in the electrolyte Electrolytes- Chemicals that conduct electric current Positive terminal- Place where positive charges collect Negative terminal- Place where negative charges collect

21. Electrical Sources Cells can be: Cells can be: Wet cells- electrolyte is a liquid Wet cells- electrolyte is a liquid Easy to make with available chemicals Easy to make with available chemicals Hard to transport and quite large Hard to transport and quite large Electrolyte Electrodes

22. Electrical Sources Dry cells- Electrolyte is a paste Dry cells- Electrolyte is a paste Easy to transport and very compact Easy to transport and very compact Special and sometimes more dangerous chemicals are required. Special and sometimes more dangerous chemicals are required.

23. Electric circuit- Load Anything that converts electrical energy into the form of energy required Anything that converts electrical energy into the form of energy required Light bulb (light energy) Light bulb (light energy) Toaster (heat energy) Toaster (heat energy) Television (light and sound energy) Television (light and sound energy) Computer (light and sound energy) Computer (light and sound energy) Fan (mechanical energy) Fan (mechanical energy) Music player (sound energy) Music player (sound energy) Motor (mechanical energy) Motor (mechanical energy)

24. Electrical circuits- Control A device that controls the flow of electrical energy A device that controls the flow of electrical energy Switches Switches Single pole switches Single pole switches Double pole switches Double pole switches 3-way switches 3-way switches Buttons Buttons Keys Keys Timers Timers Bimetallic strips Bimetallic strips Variable resistors (dimmer switches) Variable resistors (dimmer switches)

25. Electrical circuits-Connectors A conducting wire that provides a controlled path for electric current to flow to each part of the circuit A conducting wire that provides a controlled path for electric current to flow to each part of the circuit A substance where electrons can move freely from one atom to another. (electric current) Conductor- A substance where electrons can move freely from one atom to another. (electric current) Insulator- A substance where electrons cannot move freely from one atom to another. (Static electricity) Insulator- A substance where electrons cannot move freely from one atom to another. (Static electricity) Ceramics that conduct electricity with no resistance at low temperatures. (bullet trains) Superconductor- Ceramics that conduct electricity with no resistance at low temperatures. (bullet trains)

26. eeee eeee eeeee Conductor Insulator Superconductor

27. Electrical circuits Open circuit- circuit is not connected, switch is open, no electricity is flowing Open circuit- circuit is not connected, switch is open, no electricity is flowing Closed circuit- circuit is connected, switch is closed, electricity is flowing Closed circuit- circuit is connected, switch is closed, electricity is flowing Short Circuit- Circuit where there is not a load attached to the circuit, no resistance. Can be very dangerous, connectors can become overheated and burn, cells will use up the potential very rapidly. Short Circuit- Circuit where there is not a load attached to the circuit, no resistance. Can be very dangerous, connectors can become overheated and burn, cells will use up the potential very rapidly.

28. Open CircuitClosed Circuit

29. Short Circuit

30. Electrical circuits Electrical circuits can be made in two different ways. Electrical circuits can be made in two different ways. 1. Series circuit- One path of electric charge

31. Electrical circuits 2. Parallel circuit- 2 or more paths for electric charge to follow (branches)

32. Electrical circuits(10-7) Connecting cells in: Connecting cells in: Series- the potentials of the cells are added together Series- the potentials of the cells are added together ie. Three 1.5V cells connected end to end has a potential of 4.5V ie. Three 1.5V cells connected end to end has a potential of 4.5V + - ++ -- = 4.5 V

34. Electrical Circuits Parallel- the cells will last longer Parallel- the cells will last longer Potential remains the same Potential remains the same + - + - + - = 1.5V

36. Electrical circuits Connecting loads in: Connecting loads in: Series- Series- Circuit potential remains the same Circuit potential remains the same (total) Resistance is additive (total) Resistance is additive Circuits current changes according to Ohm’s law Circuits current changes according to Ohm’s law

37. 1.5V 3 Ω 4 Ω V= 1.5V R= 3Ω + 4Ω = 7Ω I = ? V = I x R I = V/R I = 1.5V/ 7Ω I = 0.21 A

38. 1.5V 5 Ω 7 Ω V= 1.5V R= 5Ω + 7Ω = 12Ω I = ? V = I x R I = V/R I = 1.5V/ 12Ω I = 0.14 A

40. Electrical circuits Parallel- Parallel- Circuits potential remains the same Circuits potential remains the same (total) Resistance decreases (total) Resistance decreases Circuits current increases according to Ohm’s law Circuits current increases according to Ohm’s law

42. Electrical circuits Pro’s and cons of series and parallel circuits. Pro’s and cons of series and parallel circuits. Series Series Pro’s Pro’s Simple to make and easy to follow. Simple to make and easy to follow. Con’s Con’s Limited control over the circuit and when one load is broken, the entire circuit won’t work. Limited control over the circuit and when one load is broken, the entire circuit won’t work.

43. Electrical circuits Pro’s and cons of series and parallel circuits. Pro’s and cons of series and parallel circuits. Parallel Parallel Pro’s Pro’s Lots of control over the circuit and not all loads have to be working at the same time Lots of control over the circuit and not all loads have to be working at the same time Con’s Con’s Much more complex and difficult to follow. Much more complex and difficult to follow.

44. Multimeter A multimeter is a device that can measure potential, current and resistance in one machine. A multimeter is a device that can measure potential, current and resistance in one machine. When using a multimeter in a circuit, it must be connected properly to get a correct reading When using a multimeter in a circuit, it must be connected properly to get a correct reading When using as a voltmeter or ohmmeter, it must be connected in parallel to the circuit When using as a voltmeter or ohmmeter, it must be connected in parallel to the circuit When used as an ammeter, it must be connected in a series in the circuit When used as an ammeter, it must be connected in a series in the circuit

45. Voltmetre or ohmmetre -Connect in parallel Multimetre Ammetre -Connect in series Multimetre

46. Circuit schematics Schematic circuit diagrams are used to show how electrical circuits are connected on paper. Schematic circuit diagrams are used to show how electrical circuits are connected on paper. Special symbols are used to indicate the different parts of the circuit. Special symbols are used to indicate the different parts of the circuit.

47. - Cell - Battery (2 cells) - Light M - Motor V - Voltmeter A - Ammeter - Switch (1 pole)

48. Making a Circuit Schematic Diagram Create a circuit that has one cell powering 1 light that is controlled by a switch.

49. Create a circuit with a 3 cell battery that has 2 lights connected in series all controlled by one switch.

50. Create a circuit with a 3 cell battery that has 2 lights connected in parallel all controlled by one switch, with another switch controlling just one of the lights.

51. Energy

52. Energy Energy- The ability to do work. Energy- The ability to do work. There are many forms of energy There are many forms of energy Light Light Sound Sound Movement (mechanical) Movement (mechanical) Heat Heat Electricity Electricity Nuclear Nuclear Chemical Chemical

53. Thermodynamics Thermodynamics is the study of moving energy. Thermodynamics is the study of moving energy. The first law of Thermodynamics says that: Energy cannot be created or destroyed. The first law of Thermodynamics says that: Energy cannot be created or destroyed. Energy can only be transformed from one form to another. Energy can only be transformed from one form to another.

54. Electricity Light

55. Energy Transformations Toaster- Electrical energy is converted to heat energy. Toaster- Electrical energy is converted to heat energy. The heat is produced by resistance inside the toaster (friction) The heat is produced by resistance inside the toaster (friction) ElectricityHeat

56. Energy Transformations Light Bulb- Electrical energy is converted to light energy Light Bulb- Electrical energy is converted to light energy Light is produced by the resistance inside the light bulb. Light is produced by the resistance inside the light bulb. ElectricityLight

57. Energy Transformations Speaker- Electrical energy is converted into sound energy. Speaker- Electrical energy is converted into sound energy. Sound is produced by having electricity turn a magnet on and off. (electromagnet) Sound is produced by having electricity turn a magnet on and off. (electromagnet) ElectricitySound

58. Energy Transformations Electric motor- Electrical energy is converted into motion (mechanical) energy. Electric motor- Electrical energy is converted into motion (mechanical) energy. Motion is produced by creating an alternating magnetic field. (electromagnet) Motion is produced by creating an alternating magnetic field. (electromagnet) ElectricityMotion

59. Electromagnets A coiled wire carrying electrical current produces a magnetic field around it. A coiled wire carrying electrical current produces a magnetic field around it. It acts like a magnet. It acts like a magnet. NS

60. Electromagnets If a piece of metal is inserted into the coil, the metal will become magnetized. If a piece of metal is inserted into the coil, the metal will become magnetized. The magnetism will only last when electricity is running through the circuit. The magnetism will only last when electricity is running through the circuit.

61. With an open circuit, there is no magnetic field. With a closed circuit, there is an electric field. NS

62. Electromagnet Metal plate

63. N S Permanent Magnet Brushes Wire coil Running electricity through a wire coil produces a magnetic field The similar poles ‘repel’ each other causing the wire coil to rotate. When the gap in the wire coil reaches the brushes, the magnetic field disappears. The wire coil will continue to rotate in the same direction, which will produce a new magnetic field in the same direction. This process continues producing a continuously rotating coil.

64. Thermodynamics The second law of thermodynamics tells us that every time energy is transformed from one type of energy to the next type, some of the energy is transformed into an unusable form. The second law of thermodynamics tells us that every time energy is transformed from one type of energy to the next type, some of the energy is transformed into an unusable form. Not all the energy is converted. Not all the energy is converted.

65. Electricity Light Heat Sound

66. Energy Loss Toaster- Electrical energy is converted to heat energy. Toaster- Electrical energy is converted to heat energy. Energy is lost in the production of light and sound. Energy is lost in the production of light and sound. ElectricityHeat Light Sound

67. Energy Loss Light Bulb- Electrical energy is converted to light energy Light Bulb- Electrical energy is converted to light energy Energy is lost as heat Energy is lost as heat ElectricityLight Heat

68. Energy Loss Speaker- Electrical energy is converted into sound energy. Speaker- Electrical energy is converted into sound energy. Energy is lost as heat and motion. Energy is lost as heat and motion. ElectricitySound Heat Motion

69. Energy Loss Electric motor- Electrical energy is converted into motion (mechanical) energy. Electric motor- Electrical energy is converted into motion (mechanical) energy. Energy is lost as heat and sound. Energy is lost as heat and sound. ElectricityMotion Heat Sound

70. Efficiency Efficiency is the comparison between the amount of useful energy produced (output energy) and the original amount of energy used (input energy). Efficiency is the comparison between the amount of useful energy produced (output energy) and the original amount of energy used (input energy). % efficiency = Useful Output Energy x 100% Input Energy Input Energy

71. Efficiency Energy is measured in Joules (J) Energy is measured in Joules (J) A regular 60W fluorescent light bulb produces 400J of light energy but it consumes nearly 2000J of electrical energy. What is the percent efficiency of a 60W fluorescent light bulb? A regular 60W fluorescent light bulb produces 400J of light energy but it consumes nearly 2000J of electrical energy. What is the percent efficiency of a 60W fluorescent light bulb?

72. Output energy = 400J Input Energy = 2000J % efficiency = ? % efficiency = Useful Output Energy x 100% Input Energy Input Energy % efficiency = 400J x 100% 2000J % efficiency = 20%

73. Can you ever have an appliance than is 100% efficient? No

74. Cost of electricity You pay for electricity based on the amount of power you use. You pay for electricity based on the amount of power you use. Power is the measure of the voltage used and the current it was used at. Power is the measure of the voltage used and the current it was used at. P = V x I Power is measured in Watts (W) Power is measured in Watts (W) A kW is 1000W A kW is 1000W

75. Cost of electricity On every electrical appliance in Canada, at least 2 out of the following 3 items have to be included. On every electrical appliance in Canada, at least 2 out of the following 3 items have to be included. Power Power Voltage Voltage Current Current Only 2 have to be included because the 3 rd can be calculated using the equation P = V x I. Only 2 have to be included because the 3 rd can be calculated using the equation P = V x I.

76. How much power is used by a light bulb that uses 120V of potential and runs at a current of 0.83A? How much power is used by a light bulb that uses 120V of potential and runs at a current of 0.83A? V= 120V V= 120V I= 0.83A I= 0.83A P= ? P= ? P = V x I P = V x I P = 120V x 0.83A P = 120V x 0.83A P= 99.6W P= 99.6W

77. What is the current used by a 60W light bulb that runs on 120V of electricity? What is the current used by a 60W light bulb that runs on 120V of electricity? P= 60W P= 60W V= 120V V= 120V I= ? I= ? P = V x I P = V x I I = P / V I = P / V I= 60W / 120V I= 60W / 120V I= 0.50A I= 0.50A

78. Cost of electricity The cost of your electricity is based on the amount of power you use (in kW), how long you use it (in hours), and the cost of the electricity (¢10.22/kW·h in Saskatchewan). The cost of your electricity is based on the amount of power you use (in kW), how long you use it (in hours), and the cost of the electricity (¢10.22/kW·h in Saskatchewan). Cost = Power x time x rate Cost = P x t x rate

79. How much does it cost to leave a 100W light bulb on for 8 hours in a day? How much does it cost to leave a 100W light bulb on for 8 hours in a day? P= 100W= 0.100kW P= 100W= 0.100kW t= 8h t= 8h Rate= ¢10.22/ kW·h Rate= ¢10.22/ kW·h Cost=? Cost=? Cost= P x t x rate Cost= P x t x rate Cost= 0.100kW x 8h x ¢10.22/kW·h Cost= 0.100kW x 8h x ¢10.22/kW·h Cost= ¢8.2 Cost= ¢8.2

80. How much does it cost to leave an equivalent 27W fluorescent light bulb on for 8 hours in a day? How much does it cost to leave an equivalent 27W fluorescent light bulb on for 8 hours in a day? P= 27W= 0.027kW P= 27W= 0.027kW t= 8h t= 8h Rate= ¢10.22/ kW·h Rate= ¢10.22/ kW·h Cost=? Cost=? Cost= P x t x rate Cost= P x t x rate Cost= 0.027kW x 8h x ¢10.22/kW·h Cost= 0.027kW x 8h x ¢10.22/kW·h Cost= ¢2.2 Cost= ¢2.2

81. Comparing Incandescent lights to fluorescent light For every 100W incandescent light bulb you have replaced with a 27W fluorescent light bulb, you will save ¢6 for every 8h of use. For every 100W incandescent light bulb you have replaced with a 27W fluorescent light bulb, you will save ¢6 for every 8h of use. If you replace 4 bulbs, that could be ¢24 a day. If you replace 4 bulbs, that could be ¢24 a day. Over 1 year that could save $87.60! Over 1 year that could save $87.60!

82. Generating electricity We have discussed several sources of electrical energy; We have discussed several sources of electrical energy; Cells Cells Batteries Batteries Photoelectric cell Photoelectric cell Generator Generator

83. Generating electricity The majority of our daily electricity comes from electricity generating stations. The majority of our daily electricity comes from electricity generating stations. All generating stations work on the same principals. All generating stations work on the same principals. We discussed earlier how current electricity in a coil produces a magnetic field. The reverse process is used to produce current electricity. We discussed earlier how current electricity in a coil produces a magnetic field. The reverse process is used to produce current electricity. A moving magnetic field produces current electricity. A moving magnetic field produces current electricity.

84. eeeeeeee S N In the presence of a magnet, the electrons are drawn in by the magnetic field. eee eee ee When the magnet moves, the electrons will be pulled along with it. The electrons are now moving, this is current electricity.

85. Generating electricity A generator uses the same materials as an electric motor, but everything happens in reverse. A generator uses the same materials as an electric motor, but everything happens in reverse. Electric motor- current electricity produces the spinning coil. Electric motor- current electricity produces the spinning coil. Generator- a spinning coil produces current electricity Generator- a spinning coil produces current electricity

86. N S The electrons are drawn to one side of the magnet so the electrons flow in one direction to that side of the magnet. e ee As the coil rotates, the electrons are again drawn to the one side of the magnet so the electrons make the trip again e ee As the coil continues to rotate, current electricity continues to flow. e ee e ee e ee e ee e ee e ee

87. Generating Electricity There are two types of electricity that can be created: There are two types of electricity that can be created: Direct current (DC)- Electricity flows in one direction (cells, generator shown) Direct current (DC)- Electricity flows in one direction (cells, generator shown) Alternating current (AC)- Electricity switches directions as the coil rotates. Alternating current (AC)- Electricity switches directions as the coil rotates.

88. eeee eeeeeeee Direct Current (DC) Alternating Current (AC)

89. Generating Electricity There are many different ways to turn the wire coil inside the generator. There are many different ways to turn the wire coil inside the generator. The coil is attached to a turbine, and the turbine is rotated by: The coil is attached to a turbine, and the turbine is rotated by: Steam (coal, nuclear, natural gas, biomass) Steam (coal, nuclear, natural gas, biomass) Water Water Wind Wind

90. Transporting Electricity Electricity has to be moved from the generating stations to peoples houses. Electricity has to be moved from the generating stations to peoples houses.

91. Most large scale generators produce around 25 000 V of electricity. The electricity is then moved to a transformer at the power plant which boosts the voltage to 400 000 V. Electricity travels more efficiently at higher voltages. The high voltage electricity is then carries by thick transmission cables made of copper or aluminum. Copper and aluminum are used because of their low resistance. The power lines go into substations near businesses, factories and homes. Here transformers change the very high voltage electricity back into lower voltage electricity. From these substations, electricity in different power levels is used to run factories, streetcars and mass transit, light street lights and stop lights, and is sent to your neighborhood. In your neighborhood, another small transformer mounted on pole or in a utility box converts the power to even lower levels to be used in your house.

92. Electricity that comes into our homes has been reduced to around 240 V. Older homes have the electricity brought in by overhead lines, newer homes have underground lines. Before the electricity is brought into your house, it is passed through a power meter to record the amount of electricity being consumed. After passing through the power meter it enters the house through the breaker box. There is one main breaker switch that controls all the electricity in the house. A breaker is a safety device that shuts the power off if the current becomes to high. Main breaker switch Inside the breaker box, the electricity can be kept at 240 V for some appliances (Oven, Furnace, etc.) or reduced to 120 V for lights and plugs. Each circuit in the house is controlled by a separate cicuit breaker. Individual circuit breakers