Lesson Plan. Course Title: Computer Maintenance Session Title: Basic Electricity/Electronics

Transcription

1 Lesson Plan Course Title: Computer Maintenance Session Title: Basic Electricity/Electronics Lesson Duration: Five 45-minute class periods (time approximate) Performance Objective: Upon completion of this assignment, students will be able to identify, demonstrate, and discuss the basics of electricity and electronics. Specific Objectives: Define the basics of electricity. Assemble and explore the basic properties of a circuit. Demonstrate and discuss the basics of the digital multimeter. Demonstrate your ability to measure resistance and continuity with the multimeter. Demonstrate your ability to measure voltage safely with the multimeter. Describe the basics of signals and noise in communications systems. TEKS Correlations: (C) employ effective reading and writing skills; Preparation 1 (D) employ effective verbal and nonverbal communication skills; 1 (E) solve problems and think critically; 1 (F) demonstrate leadership skills and function effectively as a team member; 1 (G) identify and implement proper safety procedures; 3 (D) interpret appropriate documentation such as schematics, drawings, charts, diagrams, technical manuals, and bulletins. 6 (A) use electronic test equipment to measure current, voltage, power, and resistance; 6 (B) describe digital circuits design; Instructor/Trainer References: 1. Cisco Systems Networking Academy Program: First-Year Companion Guide, Chapter 4: Layer 1: Electronics and Signals. Instructional Aids: 1. PowerPoint presentation: Basic Electricity/Electronics 2. Basic Electricity/Electronics exam 3. Labs 1 4 1

2 Materials Needed: 1. Copies of Lab Assignments (1 through 4). [For each student] 2. Various batteries (i.e. A cell, B cell, D cell, 9v and 6v lantern); for labs. 3. 1,000 Ohm and 10,000 Ohm resistors for each student or team; for labs. 4. Cat 5: jack, UTP cable, and patch cable for each student or team; for labs. 5. BNC terminated coaxial cable for each student or team; for labs. 6. Unconnected DB9 to RJ-45 adapter for each student or team; for labs. 7. Power supply (for laptop, or other networking electrical device); for labs. 8. Light switch for each student or team; for labs. 9. Copper wire; for labs light bulbs (6v) with bulb bases for each student or team; for labs. Equipment Needed: 1. Projection system to display the PowerPoint presentation (PC/Monitor, PC/Projector, etc.) 2. One digital multimeter for each student or team; for labs. 3. Wire cutter/stripper for each student or team; for labs. Learner 1. Students should read the appropriate curriculum material for how computers work (depending on the text/curriculum being used for this course). This lesson can be taught with only the PowerPoint presentation and the equipment outlined above. Introduction MI Introduction (LSI Quadrant I): After it reaches a building, electricity is carried to workstations, servers, and network devices via wires concealed in walls, floors, and ceilings. Data, which can consist of such things as text, pictures, audio, or video, travel through the wires and are represented by the presence of either electrical pulses on copper conducting wires or light pulses in optical fibers. In this lesson you learn about the basic theory of electricity, which provides a foundation for understanding how information is processed by computers and communication systems. Understanding electricity begins with understanding the basic unit of all matter the atom. Does anyone know what makes up an atom? The atom is made of three tiny parts: protons, neutrons, and electrons. The protons and neutrons are lumped together in a small grouping called a nucleus (the electrons flow freely around the nucleus). When these three parts come together, they form an atom. 2

3 Outline MI Outline (LSI Quadrant II): Instructor Notes: 1. Introduce students to the parts of an atom. 2. Introduce students to the types of electrical materials, including: a. Insulators b. Conductors c. Semiconductors 3. Introduce students to measuring electricity, including: a. Voltage (V) b. Current (I) c. Resistance (R) d. Alternating Current (AC) e. Direct Current (DC) f. Impedance (Z) 4. Introduce students to using a multimeter to make measurements, including: a. Resistance measurements b. Voltage measurements 5. Introduce students to signals and noise in communication systems. 6. Introduce students to analog and digital signaling. 7. Introduce students to simplex, half-duplex, and full-duplex transmissions. 8. Introduce students to baseband and broadband concepts. 9. Discuss signaling and communication problems with students. 10. Students complete lab demonstrations, including: a. Lab 1: Using a Multimeter b. Lab 2: Resistance Measurements c. Lab 3: Voltage Measurements d. Lab 4: Series Circuits Application MI Guided Practice (LSI Quadrant III): 1. Teacher shows and demonstrates each lab principle. 2. Teacher maintains direct supervision in the lab, providing guidance when warranted. MI Independent Practice (LSI Quadrant III): 3

4 1. Students work individually or in pairs on lab assignments, demonstrating their skills in identifying and discussing the various lab requirements and results. Summary MI MI MI Review (LSI Quadrants I and IV): 1. Ask students summary questions. a. What are the two types of electrical current? Alternating Current (AC) and Direct Current (DC) b. What measurements can be made with a multimeter? Resistance (Ohms), Voltage (AC and DC), and Continuity c. What are the three required parts of an electrical circuit? Source or battery, complete path, and load or resistance Evaluation Informal Assessment (LSI Quadrant III): 1. Monitor student progress during independent practice and provide independent re-teach/redirection as needed. Formal Assessment (LSI Quadrant III, IV): 1. Administer an objective multiple-choice test. Extension MI Extension/Enrichment (LSI Quadrant IV): Students that have mastered the lab assignments can peer-tutor students (one-onone) that are having difficulty using the multimeter. 4

5 Icon MI Teaching Strategies Verbal/ Linguistic Logical/ Mathematical Visual/Spatial Musical/ Rhythmic Bodily/ Kinesthetic Intrapersonal Interpersonal Lecture, discussion, journal writing, cooperative learning, word origins Problem-solving, number games, critical thinking, classifying and organizing, Socratic questioning Mind-mapping, reflective time, graphic organizers, color-coding systems, drawings, designs, video, DVD, charts, maps Use music, compose songs or raps, use musical language or metaphors Use manipulatives, hand signals, pantomime, real life situations, puzzles and board games, activities, roleplaying, action problems Reflective teaching, interviews, reflective listening, KWL charts Cooperative learning, roleplaying, group brainstorming, cross-cultural interactions Personal Development Strategies Reading, highlighting, outlining, teaching others, reciting information Organizing material logically, explaining things sequentially, finding patterns, developing systems, outlining, charting, graphing, analyzing information Developing graphic organizers, mindmapping, charting, graphing, organizing with color, mental imagery (drawing in the mind s eye) Creating rhythms out of words, creating rhythms with instruments, playing an instrument, putting words to existing songs Moving while learning, pacing while reciting, acting out scripts of material, designing games, moving fingers under words while reading Reflecting on the personal meaning of information, studying in quiet settings, imagining experiments, visualizing information, journaling Studying in a group, discussing information, using flash cards with others, teaching others Naturalist Existentialist Natural objects as manipulatives and as a background for learning Socratic questions, real-life situations, global problems/questions Connecting with nature, forming study groups with like-minded people Considering the personal relationship to the larger context 5

6 Computer Maintenance Basic Electronics/Electricity Exam Student Name: Date: DIRECTIONS: Circle the letter that corresponds to the best answer for each of the questions below. 1. Which of the following best describes an insulator? A. Any highly malleable metal B. Any material with a low resistance to electrical current C. Any material that cannot transmit currents over 110 volts D. Any material with a high resistance to electrical current 2. In electrical terms, what does AC mean? A. Amplified current B. Amplitude current C. Attenuating current D. Alternating current 3. Which of the following is the best definition of electrical current? A. Force or pressure caused by the separation of electrons and protons B. The measurement of electron flow in an electrical circuit C. The opposition to electron flow in a circuit D. The absence of electron flow in a circuit 4. What is the opposition to the movement of electrons as they move through materials? A. Ohms B. Voltage C. Current D. Resistance 5. Where is the safety ground connected on a computer? A. Exposed metal parts B. The monitor C. The mouse D. The network connection 6. Which of the following is the best definition of voltage? A. Force or pressure caused by the separation of electrons and protons B. The measurement of electron flow in an electrical circuit C. The opposition to electron flow in a circuit D. The absence of electron flow in a circuit 6

7 7. What is the unit of measure for resistance? A. Volt B. Ohm C. Amp D. Joule 8. When measuring voltage with a multimeter, which setting must be set? A. Amperage range B. Frequency C. Polarity D. AC or DC 9. What are the three required parts of an electrical circuit? A. Switch, source or battery, load or resistance B. Source or battery, complete path, switch C. Source or battery, complete path, load or resistance D. Power, source or battery, load or resistance 10. Which type of electrical circuit will have a continuously varying voltage-versus-time graph? A. DC B. Analog C. Digital D. Open 11. What is propagation of a network signal? A. Travel B. Delay C. Latency D. Attenuation 12. What is attenuation of a network signal? A. Travel B. Delay C. A signal losing strength to its surroundings D. A signal gaining strength from its surroundings 7

8 13. What is the result of impedance mismatch? A. Brown outs B. Power sags C. Power surges D. Reflected energy 14. Which of the following is an external source of electrical impulses that can attack the quality of electrical signals on a cable? A. EMI caused by electrical motors B. EMI caused by fiber optic cable C. EMI caused by DC batteries D. Impedance caused by radio systems 15. What is the primary cause of cross talk? A. Electrical motors and lighting B. Too much noise in a cable s data signal C. Cable wires that are too large in diameter D. Electrical noise from other wires in a cable 16. Which of the following best describes cancellation in cabling? A. Wires in the same circuit cancel each other s electrical current flow B. Twisting of wire pairs provides self-shielding within the network media C. The magnetic fields from separate cable cancel magnetic fields of another cable D. External magnetic fields cancel the fields inside network cabling 17. Which of the following terms best describe the delay of a network signal? A. Attenuation B. Dispersion C. Latency D. Jitter 18. Which of the following terms best describe two devices communicating on a shared-medium at the same time? A. Obstruction B. Dispersion C. Collision D. Latency 8

9 19. How many bits compose 1 byte? A. 2 B. 4 C. 8 D Which of the following terms best describes the conversion of binary data into a form that can travel on a physical communications link? A. Encoding B. Decoding C. Encrypting D. Decrypting 21. A channel is an allocated portion of the media s available? A. Bandwidth B. Transmission C. Simplex Transmission D. CPU processing capacity 22. What are the three parts of an atom? A. Proton, nucleus, orbit B. Electron, neutron, positron C. Neutron, electron, proton D. Proton, nucleus, positron 23. Which of the following would represent a DC source of electricity? A. An electrical generator B. A flashlight battery C. A steam engine D. A magnet 24. A multimeter can be used to measure which of the following? A. Voltage, resistance, frequency B. Voltage, resistance, continuity C. Continuity, voltage, noise D. Noise, frequency, voltage 9

10 Computer Maintenance Basic Electronics/Electricity Exam ~KEY~ Student Name: Date: DIRECTIONS: Circle the letter that corresponds to the best answer for each of the questions below. 1. Which of the following best describes an insulator? E. Any highly malleable metal F. Any material with a low resistance to electrical current G. Any material that cannot transmit currents over 110 volts H. Any material with a high resistance to electrical current 2. In electrical terms, what does AC mean? E. Amplified current F. Amplitude current G. Attenuating current H. Alternating current 3. Which of the following is the best definition of electrical current? E. Force or pressure caused by the separation of electrons and protons F. The measurement of electron flow in an electrical circuit G. The opposition to electron flow in a circuit H. The absence of electron flow in a circuit 4. What is the opposition to the movement of electrons as they move through materials? E. Ohms F. Voltage G. Current H. Resistance 5. Where is the safety ground connected on a computer? E. Exposed metal parts F. The monitor G. The mouse H. The network connection 6. Which of the following is the best definition of voltage? E. Force or pressure caused by the separation of electrons and protons F. The measurement of electron flow in an electrical circuit G. The opposition to electron flow in a circuit H. The absence of electron flow in a circuit 10

11 7. What is the unit of measure for resistance? E. Volt F. Ohm G. Amp H. Joule 8. When measuring voltage with a multimeter, which setting must be set? E. Amperage range F. Frequency G. Polarity H. AC or DC 9. What are the three required parts of an electrical circuit? E. Switch, source or battery, load or resistance F. Source or battery, complete path, switch G. Source or battery, complete path, load or resistance H. Power, source or battery, load or resistance 10. Which type of electrical circuit will have a continuously varying voltage-versus-time graph? E. DC F. Analog G. Digital H. Open 11. What is propagation of a network signal? E. Travel F. Delay G. Latency H. Attenuation 12. What is attenuation of a network signal? E. Travel F. Delay G. A signal losing strength to its surroundings H. A signal gaining strength from its surroundings 11

12 13. What is the result of impedance mismatch? E. Brown outs F. Power sags G. Power surges H. Reflected energy 14. Which of the following is an external source of electrical impulses that can attack the quality of electrical signals on a cable? E. EMI caused by electrical motors F. EMI caused by fiber optic cable G. EMI caused by DC batteries H. Impedance caused by radio systems 15. What is the primary cause of cross talk? E. Electrical motors and lighting F. Too much noise in a cable s data signal G. Cable wires that are too large in diameter H. Electrical noise from other wires in a cable 16. Which of the following best describes cancellation in cabling? E. Wires in the same circuit cancel each other s electrical current flow F. Twisting of wire pairs provides self-shielding within the network media G. The magnetic fields from separate cable cancel magnetic fields of another cable H. External magnetic fields cancel the fields inside network cabling 17. Which of the following terms best describe the delay of a network signal? E. Attenuation F. Dispersion G. Latency H. Jitter 18. Which of the following terms best describe two devices communicating on a shared-medium at the same time? E. Obstruction F. Dispersion G. Collision H. Latency 12

13 19. How many bits compose 1 byte? E. 2 F. 4 G. 8 H Which of the following terms best describes the conversion of binary data into a form that can travel on a physical communications link? E. Encoding F. Decoding G. Encrypting H. Decrypting 21. A channel is an allocated portion of the media s available? E. Bandwidth F. Transmission G. Simplex Transmission H. CPU processing capacity 22. What are the three parts of an atom? E. Proton, nucleus, orbit F. Electron, neutron, positron G. Neutron, electron, proton H. Proton, nucleus, positron 23. Which of the following would represent a DC source of electricity? E. An electrical generator F. A flashlight battery G. A steam engine H. A magnet 24. A multimeter can be used to measure which of the following? E. Voltage, resistance, frequency F. Voltage, resistance, continuity G. Continuity, voltage, noise H. Noise, frequency, voltage 13

14 Computer Maintenance Basic Electricity/Electronics Lab 1: Using a Multimeter Student Name: Date: Objective Learn how to use a multimeter correctly. Equipment The following equipment is required for this exercise: Procedures 1 st Step A digital multimeter for each student or team. A manual for the multimeter. A battery (i.e. 9v, 1.5v etc.), for each student or team to test. NOTE: The multimeter is a sensitive piece of electronic test equipment. Be sure that you do not drop it or throw it around. Be careful not to accidentally nick or cut the red or black wire leads (probes). Since it is possible to check high voltages, extra care should be taken when doing so to avoid electrical shock. Perform the following steps to become familiar with the handling of the multimeter. Insert the red and black leads (probes) into the proper jacks on the meter. The black probe should go in the COM jack and the red probe should go in the + (plus or positive) jack. 2 nd Step 3 rd Step Turn on the multimeter (click/turn the on button). What model of multimeter are you working with?. What action must you take to turn the meter on?. Switch or turn to different measurements (i.e. voltage, ohms, etc.). How many different switch positions do the multimeter have?. What are they?. 14

15 4 th Step Switch or turn the multimeter to the voltage measurement. What is the symbol for this?. 5 th Step Put the tip of the red (positive) lead on one end of a battery (+ side), and put the tip of the black (negative) lead on the other end of a battery. Is any number showing up on the multimeter?. If not make sure you switch to the correct type of measurement (Vol, voltage, or V). If the voltage is negative, reverse your leads. NOTES: 15

16 Computer Maintenance Basic Electricity/Electronics Lab 2: Resistance Measurements Student Name: Date: Objective Demonstrate your ability to measure resistance and continuity with the multimeter. Equipment The following equipment is required for this exercise: Procedures 1 st Step A digital multimeter for each student or team. A 1,000 Ohm resistor for each student or team. A 10,000 Ohm resistor for each student or team. A pencil and paper for creating graphite paths on paper. Cat 5 jack. Small (0.2m or approximately 6 to 8 inches) section of Cat 5 UTP solid cable. BNC terminated coaxial cable. Unconnected DB9 to RJ-45 adapter. Terminated Cat 5 UTP patch cable. Perform the following steps to become familiar with the handling of the multimeter. Move the rotary selector to the Omega symbol for Ohms (Ω) in order to measure resistance. Press the button that has the Ohms symbol (Ω) on it to select between resistance measurements and continuity. Resistance Measurements: The screen will show Ω (ohms), KΩ (kilohms = thousands of Ohms) or MΩ (megohms = millions of Ohms). Use the Range button to change the range of resistance to be measured based on what resistance you expect to get. If you expect low resistance (less than 10 ohms), select a low scale (like Ω). If you expect a high reading (over 10,000 ohms), select a high scale (like KΩ). If the resistance reading is over the range selected, the OL or Over Limit indicator will be displayed on the screen. The resistance setting is for measuring exact amounts of resistance. 16

17 Continuity Measurements: The screen will show a diode symbol which is a small black triangle pointing to a vertical bar. A diode is an electronic device that either passes or blocks electrical current. You may see a small sound symbol next to it, which means that when there is good continuity (no resistance) the beep will sound. The continuity setting is used when you just want to know if there is a good path for electricity or not and don t care about the exact amount of resistance. 2 nd Step Check the following resistances. Turn the multimeter off when finished or battery will drain. Item to Measure the resistance of: 1000 Ω Resistor 10 kω Resistor Graphite marking from a pencil on a piece of paper Cat 5 jack 0.2 m section of Cat 5 UTP solid cable Touch red and black probe contacts together Your own body (touch the tips of the probes with your fingers) BNC terminated coaxial cable Unconnected DB9 to RJ-45 adapter Terminated Cat 5 UTP cable Set Selector and Range Scale to: Resistance Reading: NOTES: 17

18 Computer Maintenance Basic Electricity/Electronics Lab 3: Voltage Measurements Student Name: Date: Objective Demonstrate your ability to measure voltage SAFELY with the multimeter. Equipment The following is required voltage measurement items for this exercise: A digital multimeter for each student or team. An assortment of batteries: A cell, C cell, D Cell, 9 Volts, 6 V lantern. Duplex wall outlet (typical 120v). Power supply (for laptop, or other networking electrical device). The following is optional voltage measurement items for this exercise: Procedures 1 st Step A lemon, with a galvanized nail stuck in one side, and a piece of uninsulated copper wire stuck in the opposite side. Solar cell with leads attached. Home-made generator (wire wound around a pencil 50 times and a magnet). Perform the following steps to become familiar using the multimeter for voltage measurements: Move the rotary selector to the V symbol for voltage (black V) in order to be able to measure voltage. Press the button that has the VDC and VAC symbol to select between Direct Current (DC) or Alternating Current (AC) measurements. Direct Current Measurements: The screen will show a V (voltage) with a series of dots and a line over the top. There are several scales available depending on the voltage to be measured. They start from millivolts (abbreviated mv = 1,000/th of a volt) to voltages up to hundreds of volts. Use the Range button to change the range of DC voltage to be measured based on what voltage you expect to measure. Batteries (less than 15 volts) can typically be measured accurately with the VDC scale and 0.0 range. DC voltage measurements can be used to determine if batteries are good or if there is voltage coming out of an AC adapter (transformer or converter) which are very common and used with hubs, modems, laptops, printers 18

19 and other peripherals. These adapters can take wall outlet AC voltage and step it down to lower AC voltages for the device attached or can convert the AC voltage to DC and step it down. Check the back of the adapter to see what the input (AC) and output voltages (AC or DC) should be. Alternating Current Measurements: The screen will show a V (voltage) with a tilde (~) after it. This represents alternating current. There are several scales available depending on the voltage to be measured. They start from millivolts (abbreviated mv = 1,000/th of a volt) to voltage up to hundreds of volts. Use the Range button to change the range of AC voltage to be measured based on what voltage you expect to measure. Voltage from power outlets (120v or greater) can typically be measured accurately with the VAC scale and 0.0 range. AC voltage measurements are useful in determining if there is adequate voltage coming from an AC outlet to power the equipment plugged in. 2 nd Step Check the following voltages. Turn the multimeter off when finished or battery will drain. Item to Measure the voltage of: Batteries: A cell (AA, AAA), C cell, D cell, 9 Volts, 6 V lantern Duplex wall outlet (typical 120v) Power supply (converts AC to lower AC or DC) for laptop, mobile phone, or other networking electrical device. (Optional) A lemon, with a galvanized nail stuck in one side, and a piece of uninsulated copper wire stuck in the opposite side (Optional) Solar cell with leads attached (Optional) Home-made generator (wire wound around a pencil 50 times and a magnet) NOTES: Set Selector and Range Scale to: Voltage Reading: 19

20 Computer Maintenance Basic Electricity/Electronics Lab 4: Series Circuits Student Name: Date: Objective Build series circuits and explore their basic properties. Equipment The following is required equipment for this exercise: Procedures 1 st Step A digital multimeter for each student or team. A light switch for each student or team. Wire cutter/stripper for each student or team. Copper Wire. 2 light bulbs (6v) with bulb bases for each student or team. 6-Volt lantern battery for each student or team. Perform the following steps to explore the basic properties of series circuits: Measure the resistances of all devices and components except the battery. Measure the voltage of the battery. All resistances should be less than 1 Ω (Ohm), except the light bulbs. All the devices except the battery should register continuity (with the tone) indicating a short circuit, or a conducting path. Check the following resistance. Turn the multimeter off when finished or it will drain the battery. Item to Measure the Resistance of: Pieces of wire to connect components Light switch Light bulbs Set Selector and Range Scale to: Resistance Reading: 20

21 2 nd Step Measure the voltage of the battery, unloaded (with nothing attached to it). Item to Measure the voltage of: Lantern Battery: (6 V) with no load Set Selector and Range Scale to: Voltage Reading: 3 rd Step Build a series circuit, one device at a time (use 1 battery, 1 switch, 1 bulb and connecting wires). 4 th Step Connect the battery positive lead to one end of wire and connect the negative lead to the other wire. If the switch is turned on, the bulb should light. Disconnect one thing and see that the circuit is broken. Did the bulb go out?. Measure the battery voltage while the circuit is running. 5 th Step The switch should be turned on and the light bulb should be lit. What was the voltage of the battery with the light bulb on?. Add the second bulb in series and measure the battery voltage again. NOTES: What was the voltage of the battery with the light bulb on?. 21