Basic Electricity AVTE 114 PDF

BASIC ELECTRICITY AVTE 114 1  BASIC ELECTRICITY 2 AVTE 114  BASIC ELECTRICITY WHAT IS ELECTRICITY? ❑ Electricity is all around us–powering technology like our cell phones, computers, lights, solde...

BASIC ELECTRICITY AVTE 114 1  BASIC ELECTRICITY 2 AVTE 114  BASIC ELECTRICITY WHAT IS ELECTRICITY? ❑ Electricity is all around us–powering technology like our cell phones, computers, lights, soldering irons, and air conditioners. ❑ Electricity is a natural phenomenon that occurs throughout nature and takes many different forms. ❑ Electricity is briefly defined as the flow of electric charge. 3 AVTE 114  BASIC ELECTRICITY There’s so much behind that simple statement. Where do the charges come from? How do we move them? Where do they move to? How does an electric charge cause mechanical motion or make things light up? 4 AVTE 114  BASIC ELECTRICITY Building Blocks of Atoms ❑ An atom is built with a combination of three distinct particles / elements: electrons, protons, and neutrons. ❑ Each atom has a center nucleus, where the protons and neutrons are densely packed together. ❑ Surrounding the nucleus are a group of orbiting electrons. ELECTRONS NUCLEUS - ORBITAL SHELL - + + - ELECTRONS PROTONS NUETRONS 5 AVTE 114  BASIC ELECTRICITY Building Blocks of Atoms Proton Has at least one proton in every atom Determines the atomic number of the atom Number of protons defines what chemical element Example: 1P=Hydrogen, 3P=Lithium, 29P=Copper, 94P=Platinum Balance state of an atom: number of protons is the same with the number of electrons Always carry a positive charge 6 AVTE 114  BASIC ELECTRICITY Building Blocks of Atoms Electrons Critical to the workings of electricity Always carry a negative charge Valence electrons: the electrons on the outer orbit of the atom which can escape and become free Free Electrons: allow to move charge 7 AVTE 114  BASIC ELECTRICITY Building Blocks of Atoms Neutrons Protons partner in nucleus Purpose is to keep the protons in the nucleus and determine the isotope of an atom Neutral, they have no charge 8 AVTE 114  BASIC ELECTRICITY Electrostatic Force (or Coulomb’s Law) Attraction between the nucleus and the electron Pushes away other electrons and be attracted to protons Tool we need to make electrons flow States that charges of the same type repel each other while charges of opposite types are attracted together 9 AVTE 114  BASIC ELECTRICITY Conductivity Conductivity measures how tightly bound an electron is to an atom. Conductors Metals, mostly shiny and solid Elements with high conductivity Have very mobile electrons Materials which allows in electron flow Some have malleable property, if whack with a hammer they’ll flatten into a thinner shape Examples: copper, silver, gold, iron, chromium, aluminum 10 AVTE 114  BASIC ELECTRICITY Conductivity Insulators Non-metals Elements with low conductivity Prevent the flow of electrons Examples: glass, rubber, plastic, air, selenium, sulfur Semiconductor Semi-metals Shiny but when whack with a hammer it breaks into bits Conduct electricity, dull glow of the bulb Examples: boron, silicon, germanium 11 AVTE 114  BASIC ELECTRICITY How to create flow of electrons? 1. Apply enough force to the valence electron. 2. The valence electron is ejected. 3. Free electron is created. 4. As free electron is floating, it is pulled and pushed by surrounding charges. 5. The free electron eventually finds a new atom to latch on to. 6. In doing so, another valence electron is ejected. 7. Now a new electron is drifting through space looking for the same thing. 12 AVTE 114  BASIC ELECTRICITY What is Electricity? Briefly defined as the flow of electric charge Forms of Electricity Static Electricity Current Electricity 13 AVTE 114  BASIC ELECTRICITY Static Electricity Exists when there is a build-up of opposite charges on objects separated by an insulator Exists until the two groups of opposite charges can find a path between each other to balance the system out 14 AVTE 114  BASIC ELECTRICITY Static Discharge Occurs when the charges find a means of equalizing Can flow through even the best of insulators Harmful Can result in a visible shock as the travelling electrons collide with electrons in the air Release energy in the form of light 15 AVTE 114  BASIC ELECTRICITY Ionization Note: Friction from different materials transfer electrons Ions – atoms that carry a positive or negative electric charge as a result of having lost or gained free electrons Ionization – when an electron is taken from or added to a neutral atom Positively charged Object losing electrons Positive ion (kation) Negatively charged Object gaining electrons Negative ion (anion) 16 AVTE 114  BASIC ELECTRICITY Current or Dynamic Electricity Exists when charges are able to constantly flow Requires a circuit – a closed, never ending loop of conductive material The stuff that powers electronic gadgets Charges are always on the move 17 AVTE 114