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magnetic energy for engineering students
- 1. Electricity & Magnetism Electricity& Magnetism Static, Currents, Circuits Static, Currents, Circuits Magnetic Fields & Electro Magnets Magnetic Fields & Electro Magnets Motors & Generators Motors & Generators
- 2. Facts about Magnetism Factsabout Magnetism Magnets have 2 Magnets have 2 poles (north and poles (north and south) south) Like poles repel Like poles repel Unlike poles attract Unlike poles attract Magnets create a Magnets create a MAGNETIC FIELD MAGNETIC FIELD around them around them
- 3. Magnetic Field Magnetic Field Abar magnet has a magnetic field A bar magnet has a magnetic field around it. This field is 3D in nature around it. This field is 3D in nature and often represented by lines and often represented by lines LEAVING north and ENTERING LEAVING north and ENTERING south south To define a magnetic field you need To define a magnetic field you need to understand the MAGNITUDE to understand the MAGNITUDE and DIRECTION and DIRECTION We sometimes call the magnetic field We sometimes call the magnetic field a B-Field as the letter “ a B-Field as the letter “B B” is the ” is the SYMBOL SYMBOL for a magnetic field with for a magnetic field with the the TESLA (T) as the unit TESLA (T) as the unit. .
- 4. Magnetic Force ona moving Magnetic Force on a moving charge charge If a MOVING CHARGE If a MOVING CHARGE moves into a magnetic moves into a magnetic field it will experience a field it will experience a MAGNETIC FORCE. MAGNETIC FORCE. This deflection is 3D in This deflection is 3D in nature. nature. N N S S - vo B sin qvB F B v q F B B The conditions for the force are: •Must have a magnetic field present •Charge must be moving •Charge must be positive or negative •Charge must be moving PERPENDICULAR to the field.
- 5. Atoms… Atoms… Have Have neutrons neutrons, , protons protons,and , and electrons electrons. . Protons are Protons are positively positively charged charged Electrons are Electrons are negatively negatively charged charged
- 6. Electrons… Electrons… Are located onthe Are located on the outer outer edges of edges of atoms…they can be atoms…they can be moved moved. . A A concentration concentration of electrons in an of electrons in an atom creates a net atom creates a net negative negative charge. charge. If electrons are If electrons are stripped stripped away, the away, the atom becomes atom becomes positively positively charged. charged.
- 7. + - + + + + The world isfilled with The world is filled with electrical electrical charges charges: : + + + + + - - - - - - - - -
- 8. What is thiselectrical What is this electrical potential potential called? called? Static Electricity Static Electricity - - - - - - - + + + + +
- 9. Static Electricity Static Electricity The Thebuild up build up of an electric charge of an electric charge on the on the surface surface of an object. of an object. The charge builds up but The charge builds up but does does not flow. not flow. Static electricity is Static electricity is potential potential energy energy. It does . It does not not move. It is move. It is stored stored. .
- 10. Static Discharge… Static Discharge… Occurswhen there is a Occurs when there is a loss loss of of static electricity due to three static electricity due to three possible things: possible things: Friction Friction - rubbing - rubbing Conduction Conduction – direct contact – direct contact Induction Induction – through an electrical – through an electrical field (not direct contact) field (not direct contact)
- 11. Electricity that Electricity thatmoves moves… … Current Current: The flow of electrons : The flow of electrons from one place to another. from one place to another. Measured in Measured in amperes amperes (amps) (amps) Kinetic Kinetic energy energy
- 12. How can we Howcan we control control currents? currents? With With circuits circuits. . Circuit Circuit: is a : is a path path for the flow of for the flow of electrons. We use electrons. We use wires wires. .
- 13. There are 2types of currents: There are 2 types of currents: Direct Current (DC) Direct Current (DC) – Where – Where electrons flow in the electrons flow in the same same direction in a wire. direction in a wire.
- 14. There are 2types of circuits: There are 2 types of circuits: Series Circuit Series Circuit: the components : the components are lined up along are lined up along one one path. If path. If the circuit is broken, the circuit is broken, all all components turn off. components turn off.
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- 16. There are 2types of currents: There are 2 types of currents: Alternating Current (AC) Alternating Current (AC) – – electrons flow in electrons flow in different different directions in a wire directions in a wire
- 17. There are 2types of circuits: There are 2 types of circuits: Parallel Circuit Parallel Circuit – there are – there are several several branching paths to the branching paths to the components. If the circuit is components. If the circuit is broken at any one branch, broken at any one branch, only only the components on that branch the components on that branch will turn off will turn off. .
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- 21. Conductors vs. Insulators Conductorsvs. Insulators Conductors Conductors – material through – material through which electric current flows which electric current flows easily easily. . Insulators Insulators – materials through – materials through which electric current which electric current cannot cannot move move. .
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- 23. What is Resistance? Whatis Resistance? The The opposition opposition to the flow of an to the flow of an electric current, producing electric current, producing heat heat. . The The greater greater the resistance, the the resistance, the less less current gets through. current gets through. Good Good conductors have conductors have low low resistance. resistance. Measured in Measured in ohms. ohms.
- 24. What Influences Resistance? WhatInfluences Resistance? Material of wire Material of wire – aluminum and – aluminum and copper have low resistance copper have low resistance Thickness Thickness – the thicker the wire the – the thicker the wire the lower the resistance lower the resistance Length Length – shorter wire has lower – shorter wire has lower resistance resistance Temperature Temperature – lower temperature has – lower temperature has lower resistance lower resistance
- 25. What is Voltage? Whatis Voltage? The The measure of energy measure of energy given to given to the charge flowing in a circuit. the charge flowing in a circuit. The The greater greater the voltage, the the voltage, the greater the force or “pressure” greater the force or “pressure” that drives the charge through the that drives the charge through the circuit. circuit.
- 26. Difference b/t Voltsand Amps Difference b/t Volts and Amps Example – you could say that… Example – you could say that… Amps Amps measure measure how much how much water water comes out of a hose. comes out of a hose. Volts Volts measure measure how hard how hard the water the water comes out of a hose. comes out of a hose.
- 27. Ohm’s Law Ohm’s Law Resistance= Voltage / Current Resistance = Voltage / Current Ohms = Volts / Amps Ohms = Volts / Amps
- 28. What is anelectromagnet? What is an electromagnet? Electromagnet Electromagnet – a magnet made – a magnet made from a from a current bearing coil current bearing coil of wire of wire wrapped around an wrapped around an iron or steel iron or steel core. core.
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- 30. What is agenerator? What is a generator? Generator Generator – a machine that – a machine that changes changes mechanical mechanical energy to energy to electrical electrical energy energy Usually use Usually use moving moving magnets to magnets to create create currents currents in coils of wire. in coils of wire.
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- 32. That’s It !!!! That’sIt !!!!