layari juga: kerjaya-sebagai-pendidik
Ohms Law:
Given:
E = Voltage
I = Current
R = Resistance
Then,
E=IR , boleh juga diubahsuai,
R=E/I
Basic Electrical Terms
•Definitions
–Current (I): Flow of electrons past a point. 1A = 1 coulomb of charge flowing past a point for 1 second. Unit of measure is amps.
–Resistance (R): Opposition to the flow of electrons. Unit of measure is ohms.
–Voltage: (E): Force behind electrical flow. Unit of measure is the volt.
Definitions
•Atomic Theory
–Foundation for Solid State Devices
–Atom - Smallest part of an element that retains the characteristics of that element.
–Molecule – Smallest part of a compound.
–Compound - 2 or more elements chemically combined.
The Atom
•Atom Parts:
–Electrons: Negative part of an atom.
–Protons: Positive part of an atom.
–Neutrons: Negative part of an atom.
Static Electricity
•Like charges repel each other and unlike charges attract each other.
•Walking across a wool or nylon rug , you can generate a static charge of electricity, discharging several thousand volts of electricity to a metallic object like a door handle.
Definitions
•Coulomb: Practical unit of measurement of the amount of electricity. Used to describe the flow of electricity.
–1 Coulomb = 6.24 X 1018 electrons.
•Electrostatic or Dielectric field: The field or force surrounding a charged body.
•Charge Transfer
–Direct Contact
–Induction: Electron flow due to charged object in close proximity.
Energy Band Diagrams
–
–Valence Electrons are those electrons which are located in the outermost or “Valence” shell of an atom.
–The number of valence electrons an atoms has determines the electrical properties of that atom.
< 4 electrons => Conductor
> 4 electrons => Insulator
4 electrons => Semiconductor
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