Transcript Electrons
Foundations of Technology Basic Circuits Teacher Resource – Unit 4 Lesson 4 © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology The BIG Idea Big Idea: Troubleshooting allows users to continue to use and maintain the proper operation of a system or product. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology Basic Circuits All electronic circuits have a path for electrons to flow and an energy source. Electrons will flow from the negative(-) to the positive(+). + The amount of electron flow will depend on resistance. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology - Direct Current Direct Current (DC) electrons flow in only one direction. Examples: a battery, hand held electronics such as an iPod and other devices like an automobile © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology Alternating Current Alternating Current (AC) electrons flow back and forth, negative (-) to positive (+) to negative (-) Examples: the electrical appliances at your house © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology The Atom All matter is made of atoms. e- The atom is made of three things: Protons Neutrons Electrons N e- P P N P N P N e© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology e- Electrons Electrons rotate around the group of proton and neutrons. e- When electrons move from one atom to the next, it is called electron flow. e- N P P N P N P N e- © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology e- Electrons Opposite electrical charges always attract and like electrical charges always repel. e- e- e+ e- e- Balanced atoms normally have an equal number of electrons and protons, which means they are electrically neutral. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology e- N P N P N P N P e- e- Ions Ion particles occur when an atom loses or gains an electron causing an imbalance. When an imbalance occurs, Ion's will take or release an electron to become balanced again, causing electron flow. e- e- N P P N P N P N e© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology e- Ions Ion’s can be charged: Positive (+), which has one less electron than proton. e- Negative (-), which has one more electron than proton. The positive Ion attracts to a negative Ion to become balanced. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology e- N P P N P N P N e- e- Electron Orbits Electrons rotate around the atom at different orbits. Bound electrons orbit around the nucleus on the inner rings Free electrons are loosely held and orbit around the outermost ring which is known as the valance ring © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology e- e- e- e- e- e- ee- e- e- + e- ee- e- ee- e- e- e- ee- e- e- e- ee- e- e- e- Insulators An insulator is any material that prevents the flow of electrons. Insulators typically have five to eight free electrons in the outer ring, which means they are tightly held to the atom and cannot easily move. Insulator material includes glass, rubber and plastic. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology e- e- e- ee- + ee- e- e- e- Conductors A conductor is any material that easily allows electrons to flow. Conductors typically have one to three free electrons in the outer ring, which means they are loosely held to the atom and can easily move. Conductor material includes copper and gold. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology e- ee- + e- e- Semiconductors A semiconductor is neither a good conductor or insulator. Semiconductors have exactly four free electrons in the outer orbit and are commonly used to manufacture diodes, transistors, and integrated circuit chips. Semiconductor material includes carbon, silicon, and germanium. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology e- e- e- e+ e- e- Ohm’s Law Proposed by George Ohm, and is the relationship between Voltage, Current and Resistance. Ohm suggested that if you double the Voltage across something V that provides resistance, then the current would double. + - Voltage (V) = Current (I) X Resistance (R) © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology R I Voltage Voltage is the electrical force that moves electrons through a conductor. Voltage is electrical pressure that pushes electrons. V I © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology R Current Current is the quantity or flow rate of electrons moving past a point. Current flow is also known as amperage, or amps for short. V I © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology R Resistance Resistance is the force that reduces or stops the flow of electrons and opposes voltage. V I © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology R Resistors in Series In a Series circuit, the current through two or more resistors is the same, and the circuit is connected in a series. The total resistance of the collection is the sum of the individual resistances. In series, electrons have only one path to follow to complete the circuit and must travel through all components. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology Resistors in Parallel In a Parallel circuit, the voltage through two or more resistors is the same, and the circuit is connected in parallel. The total resistance of the collection is divided among the three resistors . In parallel, electrons have multiple paths to follow to complete the circuit and do not need to travel through all components in the circuit to do so. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology Parts of the Electronics Kit 2 Battery Snaps 15 Wires Potentiometer Solderless Breadboard Diode Spea ker Battery Transist ors Photocell SCR © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology 3 LED’s 555 Timer Push Button Capacitors Parts of the Electronics Kit LED Resistor Diode Photocell 3904 Transistor Speaker 3906 Transistor Push Button “Can” Capacitor Potentiometer Ceramic Disc Capacitor © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology Battery SCR © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology 470K ohm (Yellow, Violet, Yellow, Gold) 120K ohm (Brown, Red, Yellow, Gold) 2 @ 33K ohm (Orange, Orange, Orange, Gold) 3 @ 10K ohm (Brown, Black, Orange, Gold) 16K ohm (Brown, Blue, Orange, Gold) 3.3K ohm (Orange, Orange, Red, Gold) 2.2K ohm (Red, Red, Red, Gold) 4 @ 1K ohm (Brown, Black, Red, Gold) 470 ohm (Yellow, Violet, Brown, Gold) 3 @ 330 ohm (Orange, Orange Brown, Gold) 3 @ 220 ohm (Red, Red, Brown, Gold) 2 @ 100 ohm (Brown, Black, Brown, Gold) 2 @ 47 ohm (Yellow, Violet, Black, Gold) 10 ohm (Brown, Black, Black, Gold) Parts of the Electronics Kit Color Codes Resistors have four (4) color bands on them called the “color code” Band 1 = 1st Digit Band 2 = 2nd Digit Band 3 = Multiplier. Band 4 = Tolerance Gold = 5% Silver = 10% © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology Building a Circuit The Breadboard includes two sides (a-e and f-j) and the “ditch” or the space in the middle. The holes are connected by rows not columns. © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology Practice Building a Circuit Build the circuit below: 9 Volts + - R = 1000 Ohms I 1000 ohms resistor (brown, black, red, gold) © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology Practice Building a Circuit Use your simple circuit and measure for Volts, Current and Resistance. Place the digital multimeter in series to measure current. 9 Volts Use the multimeter to measure voltage + - R I Use the multimeter to measure the resistance. 1000 ohms resistor (brown, black, red, gold) © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology Practice Building a Circuit Do the math using Ohm’s Law to find the actual value of the resistor - What does it measure? Place the digital multimeter in series to measure current. 9 Volts Use the multimeter to measure voltage + - R I Use the multimeter to measure the resistance. 1000 ohms resistor (brown, black, red, gold) © 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology