1 / 19

Electrical Engineering Topic 1: Energy, Power, Information, Current, Voltage

Electrical Engineering Topic 1: Energy, Power, Information, Current, Voltage. EGR 1301. Information iPod / music Digital cameras Radio/Television Internet/Computers Cellular telephone Satellites Embedded systems Fiber optics, lasers. Power Lighting/Appliances Motors Heating RADAR

cameron-adams
Télécharger la présentation

Electrical Engineering Topic 1: Energy, Power, Information, Current, Voltage

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Electrical EngineeringTopic 1: Energy, Power, Information, Current, Voltage EGR 1301

  2. Information iPod / music Digital cameras Radio/Television Internet/Computers Cellular telephone Satellites Embedded systems Fiber optics, lasers Power Lighting/Appliances Motors Heating RADAR Welding & manufacturing On grid / off grid EMP Information and Power

  3. Electricity Basics • Charge • The smallest unit of charge is that of an electron • Flowing charge is “Current” • Accumulated charge produces “Voltage”

  4. Electrical Conductors • Metallic bond • Electrons are shared • Valence electrons form “cloud” or “sea” of electrons • Electrons are free to flow • Causes metals to be good conductors

  5. Electrical Insulators • Covalent bond • Valence electrons are shared • BUT have to break bond in order for electrons to flow • Ionic bond • Valence electrons are transferred • Charge must be transferred by movement of entire ion

  6. Electric Current • Current  flow of positive charge “Free” electron Atom Electron Flow Current

  7. Electric Current • Hole  concept used to explain current flow • Hole = absence of an electron • An electron (-) removed from a neutral atom leaves behind a “hole” (+) A B C D E

  8. Electric Current • 1 “Coulomb” of charge is 6,241,506,360,000,000,000 electrons • If 1 Coulomb flows through a wire in 1 second, we say the current is 1 ampere or 1 “amp” • Current always “flows through”

  9. Current Magnitudes • Brain cell synaptic currents 10-13 A • Integrated circuits currents 10-4 A • Threshold of human sensation 10-3 A • Causes ventricular fibrillation 10-1 A • Household appliances 10 A • Large industrial equipment 100 A • Lightning bolt 1000 A

  10. Electrostatic Forces • Electrostatic force gives rise to stored energy • Stored energy mental images • Stretched rubber bands • Compressed springs

  11. Energy • “It is important to realize that in physics today, we have no knowledge what energy is.” – Richard Feynman, Nobel Lauriat physicist • Energy is the “stuff” that gets work done • Units of Joules, or foot pound, or calorie, or BTU, or kilowatt hour, or horsepower, etc. • “For those who want some proof that physicists are human, the proof is in the idiocy of all the different units which they use for measuring energy.” Richard Feynman • Can be thought of as a unit of exchange like money

  12. Power • Power: the rate at which energy flows from one place to another • Units: Joules/second (also called a Watt) • Helpful to think of a Watt as an energy unit per time unit • Like “mach one” is a certain number of miles per hour • Kilowatt = 1000 watts • 1 horsepower = 745.7 watts

  13. Electrostatic Force Example • Example: Calculate the force on each handful of electrons that “electric man” is holding. F F q1 q2 q1=q2=-1C r=1m r

  14. Voltage • Voltage arises from accumulated charge being separated • Opposite charges attract • Positive likes negative • Energy is required to separate them • Like the ends of a stretched rubber band • Rubber bands can be stretched to different lengths • “Voltage” is a measure of how much energy each coulomb of charge contains

  15. 120 VAC Voltage • 1 “volt” means each Coulomb of charge can release 1 Joule of energy • A 12 Volt battery will produce 12 Joules of energy for every coulomb of electrons delivered

  16. Voltage • Voltage exists between two points, • NOT at an individual point • The earth is a common reference point • “Ground” • Voltages with respect ground are like rubber bands with one end on the ground

  17. Power • Remember, power is the rate at which energy is transferred • Electric Power is found by multiplying voltage and current

  18. Power • Question: How much power is supplied to a belt sander that draws 15 amps using “wall” voltage? • Answer: 120 Volts x 15 Amps = 1800 Watts • 1800 W = 1.8 kW

  19. AC, DC, and all that • DC stands for “direct current” and means the voltage and current are constant • All batteries supply DC power • “Cigarette Lighter Power” is DC • AC stands for “alternating current” and means that the voltage and current “alternate” back and forth • Grid-supplied electric power is AC, cycling 60 times every second, or at 60 Hz.

More Related