Lesson 2 Building Blocks of Electricity PDF

BUILDING BLOCKS TO MANIPULATE ELECTRICITY (CURRENT, VOLTAGE, RESISTANCE) Current Current (I) ◻ The rate at which electrons flow past a point in a complete electrical circuit per second ◻ Ampere - Unit of measurement for current ◻ 1 Ampere = 1 Coulomb/ 1 second ? where: 1 Coulomb is...

BUILDING BLOCKS TO MANIPULATE ELECTRICITY (CURRENT, VOLTAGE, RESISTANCE) Current Current (I) ◻ The rate at which electrons flow past a point in a complete electrical circuit per second ◻ Ampere - Unit of measurement for current ◻ 1 Ampere = 1 Coulomb/ 1 second ? where: 1 Coulomb is 6.24 x 1018 electrons ◻ Andre-Marie Ampere ? French physicist and mathematician ? One of the founders of the science of classical electromagnetism Two conventions for current flow ◻ Electron Current ? Flow of electrons from low to high potential ? (Negative to Positive) ◻ Conventional Current ? Benjamin Franklin, an American scientist, theorized that the positive charge flows from high to low potentials ? (Positive to Negative) Voltage Electric Potential Energy ◻ Stored energy of a circuit ◻ Describes how much stored energy a charge has which can do work and become kinetic when set into motion by an electrostatic force ◻ Measured in units of Joules (J), which is equal to the amount of energy transferred to an object when a force of 1 Newton is applied to that object over a distance of 1 meter. Therefore, 1J = 1N*1m Electric Potential ◻ The amount of electric potential energy divided by the amount of charge at any point in the electric field ◻ Comes in units of Joules per Coulomb (J/C) which is defined as a volt (V). Therefore, 1V=1J/1C ◻ Example: 10 Volts means that one Coulomb of charge at the higher potential end can do 10 Joules of work on its way down to the lower potential end Voltage (V) ◻ Also called Potential Difference, Potential, EMF ◻ Electrical pressure ◻ Has potential to do work ◻ Difference in charge between two points ◻ The measure of the push on each electron which makes the electron move ◻ Alessandro Volta ? Italian Physicist ? Invented the first chemical battery Voltage ◻ Example: ? In 1.5V battery, if 1 Coulomb of charge came out of one side, it could do 1.5 Joules of work before re- entering the other side of the battery. ? If battery connected to a light bulb, each Coulomb that came out of the top of the battery and went through the light bulb would give off 1.5J of light and heat before it re-entered on the other side. Resistance Resistance ◻ Opposition to current flow ◻ Acts to oppose motion and generate heat ◻ Limits the flow of electrons through a circuit ◻ Materials with tendency to resist the flow of charge ◻ Unit of measure is Ohm (Ω) ◻ The resistance between two points where 1V of applied potential energy will push 1A of current. Therefore, 1Ω = 1V/1A Factors that determine resistance ◻ The material itself ? Silver > copper > aluminum ◻ Cross-sectional area ? The end or tip of the wire you cut ? Small cross-sectional area, higher resistance ? Large cross-sectional area, lower resistance ◻ Length ? Longer conductor, higher resistance ◻ Temperature ? Temperature increases, higher resistance ? Cool wire, lower resistance Georg Ohm ◻ German physicist and mathematician ◻ In 1825, experimented with early chemical batteries and thermocouples to produce voltages ◻ Determined Voltage and Current were proportional RESISTOR Resistor ◻ A passive component since it only consumes Schematic Symbol power and can’t American- International- generate it style style ◻ A resistor is an electrical component that limits or regulates the flow of electrical current in an electronic circuit. Types of Resistors ◻ Through-hole (PTH) ? Come with long pliable leads which can be stuck into a breadboard or hand-soldered into PCB ◻ Surface-mount ? Tiny black rectangles, terminated on either side with even smaller, shiny, silver, conductive edges ? Sit on top of PCBs, soldered in place by a robot and sent through an oven where solder melts ? Advantages: mass circuit board protection, space Decoding Resistor Markings ◻ 1st and 2nd bands indicate the two most significant digits ◻ 3rd band is the weight which multiplies the two significant digits by the power of 10 ◻ 4th band indicates the tolerance Decoding Resistor Markings Color Digit Value Multiplier Multiplied out Tolerance Black 0 100 1 Brown 1 101 10 Red 2 102 100 Orange 3 103 1000 Yellow 4 104 10000 Green 5 105 100000 Blue 6 106 1000000 Violet 7 107 10000000 Gray 8 108 100000000 White 9 109 1000000000 Gold + 5% Silver + 10% Example Exercise Prefixes Number Prefix Symbol Scientific Notation 1,000,000,000,000 Tera T 1x1012 1,000,000,000 Giga G 1x109 1,000,000 Mega M 1x106 1,000 Kilo k 1x103 100 Hecto h 1x102 10 Deka dk 1x101.1 Deci d 1x10-1.01 Centi c 1x10-2.001 Milli m 1x10-3.000,001 Micro µ 1x10-6.000,000,001 Nano n 1x10-9.000,000,000,001 Pico p 1x10-12 Exercises 1.) 2.) Blue, Red, Brown, Gold 3.) Green, Violet, Black, Gold 4.) Orange, Red, Yellow, Gold 5.) Red, Green, Blue, Gold Exercises 1.) 30 Ω +5% 2.) 120 Ω +5% 3.) 32 kΩ +5% 4.) 6 MΩ +5%