Unit 2: ANALOG ELECTRONICS
Time: 38 Hours
Description
In this unit students perform a series of circuit construction activities to develop an understanding of analog components and circuit design. Students develop practical skills in troubleshooting and continue to demonstrate safe work practices in an electronic shop environment. Students learn the basis for electronic signal production and manipulation, particularly in the area of sound amplification and reproduction. Subsequently, students examine the procedures in creating printed circuit boards and the manufacturing processes in communication electronics.
Expectations
The following expectations are covered in this unit’s activities:
Strand / Overall / SpecificTheory and Foundation / TVF.02.1W TVF.03.1W / TF2.05.1W TF2.07.1W
TF2.08.1W
TF2.10.1W TF2.12.1W / TF2.13.1W TF2.14.1W TF3.01.1W TF3.02.1W TF3.01.1W
TF3.02.1W
Skills and Processes / SPV.01.1W
SPV.02.1W
SPV.04.1W / SP1.01.1W SP1.02.1W SP1.03.1W SP2.01.1W SP2.02.1W SP2.04.1W / SP2.05.1W SP2.06.1W SP3.01.1W SP4.01.1W SP4.02.1W SP4.03.1W
Impact and Consequences / IC2.01.1W / IC2.02.1W
See Appendix E for full description of TGJ3E expectations
HRDC NOC Specialized Skills
The activities in this unit are designed for occupations that require troubleshooting electrical signals, designing and building analog circuits, writing test reports, reading schematics and using testing equipment. Though most careers identified by HRDC as related to electronics can benefit from the skills and knowledge addressed in this unit, the following career categories are directly related to the activities in this unit:
2133
/Electrical and Electronics Engineers
2241
/Electrical and Electronics Engineering Technologists and Technicians
2242
/Electronic Service Technicians (Household and Business Equipment)
2243
/Industrial Instrument Technicians and Mechanics
2244
/Aircraft Instrument, Electrical and Avionics Mechanics, Technicians and Inspectors
7245
/Telecommunications Line and Cable Workers
7246
/Telecommunications Installation and Repair Workers
7247
/Cable Television Service and Maintenance Technicians
7332
/Electric Appliance Servicers and Repairers
9483
/Electronics Assemblers, Fabricators, Inspectors and Testers
9484
/Assemblers and Inspectors, Electrical Appliance, Apparatus and Equipment Manufacturing
Activities
The activities in this unit are designed to be sequential to give the student progressive challenges in circuit design, build and testing. Students learn the theory of electronics and analog circuitry through hands-on projects that are based on signal processing, measuring and calculation electrical parameters, and use of test instrumentation. By concentrating on the audio and visual portion of the electromagnetic spectrum, these projects are related to media productions in communications technology, and will give students the basic principles of telecommunications and photonics in later projects.
Activity / Activity Title / Time (minutes)1 / The 555 Timer / 480
2 / Audio Electronics: Signal Processing / 600
3 / Project Loudspeaker / 1200
Prior Knowledge
Students should have some knowledge of basic test equipment and electronic principles as outlined in Unit 1. Teachers should review acceptable Internet use policies as established by the school board.
Before working in a shop environment, students must be aware of general shop rules and requirements, as well as safety rules for specific tools and machines (e.g. safe operation, guard placement and the use of safety glasses). Teachers should review safety rules discussed in Unit 1, and initiate discussion of new tools and processes to be used in this unit. Teachers must verify student’s knowledge of any new safety issues through either a signed “safety passport’ (Appendix B), and/or a check on safety knowledge. Shops must be kept professionally clean at all times. It is to the student's benefit to spend time at the end of each class to prepare the lab for the next class.
Unit Planning Notes
The activities in this unit are designed to provide the opportunity for students to see how electronic circuits and components perform, (particularly analog circuits), how to solve problems with electronic circuits, how to problem solve with prototyping and design procedures, and how to manufacture circuits using industry procedures.
Students are expected to maintain the technician’s test bench developed in Unit 1. (Refer to Unit 1: Activity 2). Teachers must remind all students that they must not turn on any circuit until it is approved and signed off. This unit requires a hands-on approach to circuit design and building, and therefore requires the preparation of physical resources, test equipment and associated tools.
If not already completed, the following tools should be prepared before initiating the activities:
Test bench equipment:· oscilloscope
· multimeter
· signal generator (suggested)
· DC power supplies
· batteries
· circuit simulation software
· wire cutters
· wire strippers
· needle nose pliers
· safety eyewear / Shop Equipment
(for speaker cabinets or project boxes)
· table saw (with dado blades for rabbit cuts (optional))
· jointer
· sander
· jigsaw/scrollsaw
· router
· Dremel tool
· nibbler (optional)
· nail gun (optional)
· power screwdriver (optional)
Supplies:
· 555 timer
· 556, 558 timers, (optional)
· magnet wire or choke coils
· variety of diodes, transistors
· variety of inductors
· L-Pads
· speaker wire
· loudspeakers
· jumper wires, or multi-conductor wire
· breadboards / · bins (i.e. Tupperware-type) for parts of student projects
· solder equipment and associated supplies
· (tweeter/midrange/woofer/subwoofer) as required
· MDF sheets, stick lumber for loudspeaker cabinets
· variety of capacitors and/or variable capacitors
· variety of resistors and/or variable resistors
Aspects of these activities are integrated with curriculum from other courses. For example: English expectations of report writing, research and technical documentation skills, Physics and Mathematics expectations for understanding the theoretical aspects of electronics overlap with the material in this unit. Computer courses, in particular Computer Engineering, are useful in dealing with knowledge of computer-based electronic applications and control systems. Design Technology will enhance understanding of consumer electronic product design and the product development process.
It would be beneficial if representatives from local manufacturing industries present in class or conduct tours. Visiting local colleges, university or private electronics labs are recommended for students to develop an awareness of typical electronics facility operations.
Teaching / Learning Strategies
This unit continues the hands-on project orientation with a variety of teaching and learning strategies, as described in Unit 1. Students will use their test bench setups (from Unit 1) in activities that incorporate designing/ building/ troubleshooting of analog electronic circuits.
Teachers should present students with an itemized list of tasks that need to be accomplished, including timeframes. Students must keep a daily log of their activities. Teachers should arrange activities to keep students busy at all times, i.e. report writing or drawing/illustration while awaiting paint drying or computer resources. Teachers may elect to post the current status of project tasks in the room for planning purposes.
The activities in this unit are designed as "Just In Time" activities, in other words, the facts or skills that are required for a particular task are taught just before they are needed. For example, when students require a resistor for their first circuit (Activity 1), they are presented with the resistor colour code and the use of resistive elements to control voltage or current to use in the activity.
Activity 1 engages students in investigating the physical parameters and usage of typical electronic devices and components. The first activity, using a 555 timer, it takes the student through the entire process of component designing, breadboard prototyping, computer based circuit simulation, and mathematical calculations in circuit design. Activity 2 involves an investigation of electrical signals through the fabrication and testing of an audio amplifier and loudspeaker crossover filter network. Activity 3 involves fabrication of printed circuit boards (PCB). Through these activities, students should have a good grounding in electronic circuit design and components and the measurement and manipulation of electrical signals.
Teachers can accommodate the variable learning rates of students by allowing increased time for activities, enhancing or compacting course content, assisting during evaluation processes, and/or facilitating peer-tutor assistance where possible.
Note: A construction shop has a different set of safety issues than the electronics facility. Teachers must be qualified to operate in a construction shop facility. A team-teaching approach may be necessary to take advantage of teachers’ individual strengths.
Assessment / Evaluation
Teachers must ensure that all students have an opportunity to demonstrate their mastery of the course expectations individually, even when working in a group. This can be accomplished through one-on-one daily conferencing, daily journal log entries, individual deliverables such as reports or presentations, or individually signed elements of reports or forms.
Assessment is an on-going daily process that may include review of a daily/weekly log, (See Appendix D: Sample Daily Log), observations of efforts in problem solving and critical thinking, participation in discussions and self and/or peer critiques. Students are evaluated on project deliverables such as completed circuit designs, test or project synopsis reports, and presentations based on the assessment charts presented in each activity.
Resources
Crocodile Clips Simulation Software
Spectrum Educational Supplies125 Mary Street
Aurora, Ontario L4G 1G3
Phone: 905-727-6265 http://www.spectrumed.com /
Electronic Workbench Simulation Software
111 Peter Street, Suite 801Toronto, Ontario M5V 2H1
Phone: 416-977-5550 ext. 255
Reference Texts
Electronic Dictionary
Art of ElectronicsRadio Shack booklists /
Reference Materials
Telephone DirectoriesIndustrial Directories
Internet Sites
How Things Work- http://www.howthingswork.com/
Nuts and Volts Magazine- http://www.nutsvolts.com/
Unit 2 Overview - 23 - TGJ3E (Microelectronics)
The 555 Timer
Unit 2 Activity 1
480 minutes
Description
Students construct an astable oscillating circuit using the 555 timer IC. Students compare the results of formula calculations, circuit simulation software and circuit measurement results to ensure accuracy of calculations and measurements. Students develop a series of circuits based on the 555 timer IC to develop skills in circuit design, fabrication, testing and troubleshooting.
Strands and Expectations
Strand / Overall / SpecificTheory and Foundation / TVF.02.1W / TF2.07.1W
TF2.08.1W
TF2.10.1W / TF3.01.1W
TF3.02.1W
Skills and Processes / SPV.01.1W
SPV.02.1W
SPV.04.1W / SP1.01.1W SP1.02.1W SP1.03.1W SP2.01.1W SP2.02.1W SP2.04.1W / SP2.05.1W SP2.06.1W SP3.01.1W SP4.01.1W SP4.02.1W SP4.03.1W
Impact and Consequences / IC2.01.1W / IC2.02.1W
See Appendix E for full description of TGJ3E expectations
HRDC NOC Specialized Skills
2133 Electrical and Electronics Engineer
2133.1.1 2133.1.2 2133.1.3 2133.1.4 2133.1.6
2241 Electrical and electronics engineering technologists and technicians
Technologists 2241.1.1 2241.1.2 2241.1.3 2241.1.5
Technicians: 2241.2.1 2241.2.2 2241.2.4 2241.2.5 2241.2.6
2241.2.7 2241.2.8
2242 Electronic service technicians (household & business equipment)
2242.1.3 2242.1.4
7332 Electric appliance servicers and repairers
Small Appliance Repairers 7332.1.4
7245 Telecommunications line and cable workers
7245.1.5
7246 Telecommunications installation and repair workers
Telecommunications Service Testers 7246.3.2
9483 Electronics assemblers, fabricators, inspectors and testers
Assemblers 9483.2.2 9483.3.5 9483.4.1 9483.1.1
See Appendix F for full description of NOC Specialized Skills
HRDC NOC Essential Skills
· numeracy / · decision making / · writing· problem solving / · reading / · using documents
See Appendix A for Essential Skill rubrics
Prior Knowledge
As students will use the test bench established in Unit 1, prior knowledge includes:
1. basic test equipment identification and associated terminology;
2. basic safety procedures, (but should be reviewed in any case);
3. simple algebraic equation manipulation;
4. simple graphic and report production techniques.
Planning Notes
Teachers must arrange the following equipment and supplies. Safety glasses should be made available to participants of the equipment tear down, ideally all students should be issued safety eyewear.
Test bench equipment:· Oscilloscope
· function generator (for demo)
· stop watch
· frequency counter
· multimeter
· capacitance meter
· DC power supplies or batteries (9V)
· circuit simulation software
· wire cutters
· wire strippers
· needle nose pliers
· safety eyewear
· calculators / Supplies:
· 555 timer
· 556, 558 timers, (optional)
· variety of capacitors and/or variable capacitors
· variety of resistors and/or variable resistors
· jumper wires, or multi-conductor wire
· breadboards
· bins (i.e. Tupperware-type) for parts of student projects
· small speakers for sound generator experiments
Other resources necessary for this activity include:
· teacher-developed handout detailing assignment requirements, (Appendix 2.1.1);
· handout detailing schematic circuit for a 555 oscillating multivibrator (Appendix 2.1.2)
· handout detailing test report format (Appendix 2.1.3)
· sample working prototype (optional)
By introducing electronic circuit components and circuit basics in the context of solving a specified problem, students can be taught the basics of analog electronics and electronics theory to be applied in any further circuit-design problem. This hands-on approach is meant to take the place of "theory lessons" conducted in isolation of the application. Teachers will demonstrate components and techniques and allow time for students to apply this knowledge to the task of circuit building
Teaching / Learning Strategies
In this activity students build a 555 timer-circuit (multi-vibrator) from a schematic diagram to a specified frequency. This activity aims to develop the skills of schematic reading, circuit prototyping and testing, troubleshooting and test report writing. Students build a variety of circuits based on the 555 timer.
Stage 1
The first stage of this activity is divided into three components:
1. Calculating frequency of a 555 timer circuit using the mathematical formula;
2. Calculating frequency of a 555 timer circuit using circuit simulation software;
3. Calculating frequency of a 555 timer circuit by constructing a physical circuit and measuring resulting frequency.
In using these 3 methods, students can observe the importance of verifying results through a variety of methods. Students will also review the methods used to verify and troubleshoot electronic circuits.
Students are arranged in pairs or teams as required by classroom resources. (Ideally students work individually).
Students are handed the Project Design Brief, outlining the schematic of the multi-vibrator, the deliverables and associated timelines (Appendix 2.1.1). Teachers describe the procedures of prototyping circuits using breadboards, and reinforce their knowledge of Ohm's Law and the physical relationship of voltage/current/resistance. Electron flow and the basic elements of circuits such as power source, conductive paths and load are discussed. Basic passive components are demonstrated: resistor, capacitor, LED, IC, power source and other load components such as bells, speakers, buzzers, motors, etc.