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Electric Circuit Theory

Electric Circuit Theory. The Atom & Ohm’s Law. First, lets look at the Atom. Orbit. Electron. Neutron. Proton. Nucleus. Valence Electrons. Electronics focuses on the electrons in the Valence Orbit. Valence electrons are more loosely bound to the atom and easier to move.

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Electric Circuit Theory

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  1. Electric Circuit Theory The Atom & Ohm’s Law

  2. First, lets look at the Atom Orbit Electron Neutron Proton Nucleus

  3. Valence Electrons Electronics focuses on the electrons in the Valence Orbit Valence electrons are more loosely bound to the atom and easier to move Too tightly bound to easily move http://www.chemtutor.com/struct.htm

  4. Silver Gold Copper Conductors 3 or Less Electrons in the Valence Shell 2nd 1st 3rd

  5. 1. Superconductors 2. Gold 3. Silver 4. Copper Top 4 conductors

  6. HTS – High Temperature Superconductors 2001 Japan – magnesium diboride – 39 degrees Kelvin "Second generation" HTS wire can carry the same amount of current as copper wire hundreds of times as thick.

  7. Oxygen Neon Insulators 6 or More Electrons in the Valence Shell

  8. Germanium Silicon Semi-Conductors 4 or 5 Electrons in the Valence Shell

  9. Insulator Semiconductor Conductors

  10. A basic circuit… + 3. Load _ 1. Power Source 2. Pathway In this Closed Loop circuit electrons flow from negative to positive THROUGH the load and work gets done

  11. The four parts of a basic circuit… + _ 4. Control 3. Load 1. Power Source 2. Pathway If the pathway from negative to positive is broken no electrons will flow and no work gets done. This is the function of every switch: to control the flow of electrons by “opening” and “closing” the circuit.“OFF and ON”

  12. What is Voltage? Named after Alessandro Volta who invented the first practical battery in 1799 "Reason to Move" or "Push" Potential - Electrons don’t “want” to move from one atom to another. Any force chemical, magnetic, mechanical or whatever that gives them a “Push” or “Reason to move” from one atom onto another is called a voltage.

  13. What is Resistance? No this is not named after anyone named “Resist.” It is as the name implies… ”Opposition to Movement.” All loads and all wires except superconductors have some amount of resistance "Opposition to Movement" Resistance is Measured in OHMS and this unit of measurement IS named after the mathematician who discovered the most fundamental law governing the study of electricity… OHM’s LAW. His name was Georg Simon OHM.

  14. What is Amperage? Named after Andre Marie Ampere, a mathematician who formulated theories that greatly helped solidify the link between electricity and magnetism. "Amount Per Time" This is the Dangerous part of electricity. Roughly 0.5 Amps of electricity is enough to kill a person.

  15. Ohm’s Law: The relationship between Voltage, Resistance, and Amperage Lets Use an Analogy! A power source initiates electric flow by creating a Voltage, or a difference in potential between two points of a closed circuit. Voltage of course, is a dependent variable…. The circuit load, the other dependent variable, measured in units of resistance, is what opposes this push of electrons through the circuit… Blah blahblahblah

  16. Ohm’s Law Analogies Voltage or “Reason for electrons to Move” Resistance to Movement Amperage: The number of mice per unit of time that make it to the cheese Electrons

  17. Ohm’s Law Analogies What are TWO things that can be done to INCREASE the Amperage?

  18. Ohm’s Law Analogies Resistance Voltage Amperage = 50 mice /Second Electrons DECREASING resistance in a circuit will raise the amperage in the same circuit proportionally OR…

  19. Ohm’s Law Analogies Resistance Voltage Electrons Leaving the resistance alone but INCREASING the voltage will also raise the amperage proportionally.

  20. Ohm’s Law Analogies Voltage Resistance Electrons What are TWO things that can be done to DECREASE the Amperage?

  21. Ohm’s Law Analogies Voltage Electrons Resistance INCREASING resistance in a circuit will decrease the amperage in the same circuit proportionally OR…

  22. Ohm’s Law Analogies Voltage Resistance Electrons DECREASING voltage in a circuit will decrease the amperage in the same circuit proportionally

  23. What Happens when… Resistance Amperage ?? Voltage Amperage ??

  24. Ohm’s Law Resistance Amperage ?? Voltage Amperage ?? Inversely Proportional Directly Proportional

  25. Ohm’s Law Analogy dsgdsafg dsgdsafg dsgdsafg • Electrons: lkjlakjsdioj • Resistance: lkjsalkfjoijsdl • Voltage: oikjlkjj • Amperage: lkjlkjlksajldkfjlksjdlkfjlksjflsjlksjlksdjlsjd • Two Ways to INCREASE Amperage: • Jdsfkljsadfkljsafjdkljsadfkljsadfjfjdskldsajsdafd • Fadfadfadfadsssdkjsf;flkjdf;lkjadf;lkajdf;laskdjf • Two Ways to DECREASE Amperage: • Dnfkljasdihjiafheansfnfeklanwfiejenfansdfnasfd • Fakjdf;lakjdfl;akdjfl;akdjflkkjfkdkjfliheirouaepoo Your Turn… • Assignment Title, • Your Name, • Date, • Class Period, • Teacher’s Name HOMEWORK ASSIGNMENT Create your Own Ohm’s Law analogy on a single sheet of paper. It must contain: • A drawing with labels of each part of the analogy • electrons • resistance • voltage • A written description of what represents the electrons, resistance, voltage, and amperage. • A written description of the TWO ways in which the amperage can be raised and the TWO ways amperage can be lowered. Name Date Period Teacher’s Name

  26. Ohm’s Law (The Math) E = IR E = Voltage I = Amperage R = Resistance You may have heard of it this way: V = IR

  27. Ohm’s Law • “OK” …you say….I get that “R” is for Resistance but WHY the E and I?? • Before Volts were named after Volta, it was simply called “Electro-motive Force” or backwards, “the force that moves electricity”… so…. “E” just stuck to represent voltage when doing calculations

  28. Ohm’s Law • Alright but what about “I”?? • Before Amperage was named after Ampere it was called “Intensity”

  29. Let’s do math! Pretend one of your classmates, ( go ahead pick one), placed their head where normally a light bulb would go in a circuit. Their head is now the “load”. Every load has an amount or value of resistance to electron movement.

  30. Let’s do math! In the language of Baseball……He is outta’ there! In the language of Food……He is Toast! You get the picture… 10 Ohms 100 V What two things can you do to save this person?

  31. Only Three Circuits to Learn… There are only three ways to hook up an electric circuit. If you learn all three and how electricity moves through them, then you understand the fundamental principals of how ALL of electronics works. -

  32. Series Circuit • Only ONE pathway from negative to positive • If one light bulb burns out the rest will not work and you are in serious trouble. The “Extra Bulb”

  33. Parallel Circuit • More than ONE pathway from negative to positive • If one light bulb burns out it will not affect the rest.

  34. Series-Parallel Circuit • Both Series and Parallel sections within the circuit. • If one light bulb burns out it may affect other parts of the circuit

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