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
Theory and Foundation
Skills and Processes
Impact and Consequences
Specific
TF2.13.1W
TF2.05.1W
TF2.14.1W
TF2.07.1W
TVF.02.1W
TF3.01.1W
TF2.08.1W
TVF.03.1W
TF3.02.1W
TF2.10.1W
TF3.01.1W
TF2.12.1W
TF3.02.1W
SP1.01.1W
SP2.05.1W
SP1.02.1W
SP2.06.1W
SPV.01.1W
SP1.03.1W
SP3.01.1W
SPV.02.1W
SP2.01.1W
SP4.01.1W
SPV.04.1W
SP2.02.1W
SP4.02.1W
SP2.04.1W
SP4.03.1W
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
Unit 2 Overview
- 23 -
TGJ3E (Microelectronics)
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
1
2
3
Activity Title
The 555 Timer
Audio Electronics: Signal Processing
Project Loudspeaker
Time
(minutes)
480
600
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:
Shop Equipment
(for speaker cabinets or project boxes)
 oscilloscope
 table saw (with dado blades for rabbit
 multimeter
cuts (optional))
 signal generator (suggested)
Unit 2 Overview
- 24 -
TGJ3E (Microelectronics)







DC power supplies
batteries
circuit simulation software
wire cutters
wire strippers
needle nose pliers
safety eyewear
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








jointer
sander
jigsaw/scrollsaw
router
Dremel tool
nibbler (optional)
nail gun (optional)
power screwdriver (optional)

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
Unit 2 Overview
- 25 -
TGJ3E (Microelectronics)
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 Supplies
125 Mary Street
Aurora, Ontario L4G 1G3
Phone: 905-727-6265
http://www.spectrumed.com
Electronic Workbench Simulation Software
111 Peter Street, Suite 801
Toronto, Ontario M5V 2H1
Phone: 416-977-5550 ext. 255
Reference Texts
Electronic Dictionary
Art of Electronics
Radio Shack booklists
Reference Materials
Telephone Directories
Industrial Directories
Internet Sites
How Things WorkNuts and Volts Magazine-
Unit 2 Overview
http://www.howthingswork.com/
http://www.nutsvolts.com/
- 26 -
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
Theory and Foundation
TVF.02.1W
Specific
TF2.07.1W
TF2.08.1W
TF2.10.1W
TF3.01.1W
TF3.02.1W
SP1.01.1W
SP2.05.1W
SP1.02.1W
SP2.06.1W
SPV.01.1W
SP1.03.1W
SP3.01.1W
SPV.02.1W
SP2.01.1W
SP4.01.1W
SPV.04.1W
SP2.02.1W
SP4.02.1W
SP2.04.1W
SP4.03.1W
IC2.01.1W
IC2.02.1W
See Appendix E for full description of TGJ3E expectations
Skills and Processes
Impact and Consequences
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
2241.2.7
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
2241.2.6
See Appendix F for full description of NOC Specialized Skills
HRDC NOC Essential Skills


numeracy
problem solving
Unit 2: Activity 1


decision making
reading
- 27 -
 writing
 using documents
See Appendix A for Essential Skill rubrics
TGJ3E (Microelectronics)
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:
Supplies:
 Oscilloscope
 555 timer
 function generator (for demo)
 556, 558 timers, (optional)
 stop watch
 variety of capacitors and/or variable
capacitors
 frequency counter
 variety of resistors and/or variable
 multimeter
resistors
 capacitance meter

jumper wires, or multi-conductor wire
 DC power supplies or batteries (9V)
 breadboards
 circuit simulation software
 bins (i.e. Tupperware-type) for parts of
 wire cutters
student projects
 wire strippers
 small speakers for sound generator
 needle nose pliers
experiments
 safety eyewear
 calculators
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;
Unit 2: Activity 1
- 28 -
TGJ3E (Microelectronics)
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.
Teachers describe the concepts of frequency, amplitude and electromagnetic waves. Teachers
demonstrate the types of waves (square, sine, sawtooth) and the meaning of frequency and amplitude
through the use of a function generator and oscilloscope. Teachers then describe how the 555 timer
can be used to generate a square wave signal of determined frequency dependent on the values of
external resistors and capacitors.
Teachers illustrate the formula for calculating frequency of the multivibrator, and set the target
frequency for the student's first circuit, (a visible frequency such as 1 or 2 Hz). Students then calculate
the values for components for their circuit by manipulating the equation. Students record their
calculations in their test report notes.
Teachers demonstrate the symbols of a schematic diagram and their physical counterparts. After a
brief introduction to resistors and the resistor colour code, Students then locate the appropriate values
for their circuits. This is repeated for capacitors and LEDs. Safe handling and operational parameters
of the 555 are discussed and given to students. Students collect their components and assemble the
circuit with assistance from the teacher.
When teachers give the OK, students power their circuit and time their resultant frequency (through
stopwatch or frequency counter). Students use troubleshooting techniques to determine problems if
required. When successful, students will record results in their test report notes.
If available, students use circuit simulation software (such as Electronic Workbench, Tina or Crocodile
Clips) to build a virtual representation of their circuit. Students run the simulation and obtain the
frequency using the measured values of the physical components.
Students compare notes of the three methods of determining frequency, and make observational
comments as to the closeness of the values. If any result is significantly apart from the others, or all
three are different, then the student must record these results and diagnose the reasons for the
discrepancy.
Stage 2
Students are given circuit diagrams of other circuits based on the 555 timer. The students task is to
complete each circuit and compose a test report. These circuits include: (see Resources for this
activity for circuit ideas)
 astable multivibrator with speaker in place of LED
 pulse generator (given a frequency, determine component values)
Unit 2: Activity 1
- 29 -
TGJ3E (Microelectronics)










toy organ
chirp generator
sound effects generator
tone burst generator
stepped-tone generator
monostable or one-shot trigger
cascaded timer (using two 555s or a 556)
intervalometer
event-failure alarm
frequency divider
Teachers may elect to test student's knowledge of vocabulary through oral presentations or written
tests.
Vocabulary
Students should be able to define the following terms, components and/or processes:
 analog electronics
 digital electronics
 resistance
 resistor
 ohms
 colour code
 Voltage
 EMF
 DC
 Current
 ampere
 load
 IC
 555 timer
 diode
 LED
 capacitance
 capacitor
 Farads
 frequency
 amplitude
 period
 pulse width
 duty cycle
 monostable
 astable multivibrators
 switch debouncer
 electromagnetic wave
 sine wave
 square wave
 Hertz (Hz)
 function generator
 voltmeter
 ohmmeter
 capacitance meter
 frequency counter
 oscilloscope
 time base
 beadboard
 SI measurements: pico, micro, milli, kilo, mega
Assessment / Evaluation
Students will be assessed and evaluated on several aspects of this project:
 demonstration of vocabulary knowledge (verbally, oral presentation, written test);
 test reports (initiative, depth of content, presentation, originality);
 verbal presentation (depth of understanding of subject, quality and effort of presentation).
Unit 2: Activity 1
- 30 -
TGJ3E (Microelectronics)
555 Timer Assessment Rubric
Criteria
Students will:
Knowledge
TVF.02.1W
TF2.07.1W
TF2.08.1W
TF2.10.1W
TF3.01.1W
TF3.02.1W
Inquiry
SPV.02.1W
SP2.04.1W
SP2.05.1W
SP2.06.1W
Communication
SP1.03.1W
SP2.01.1W
SP3.01.1W
SP4.02.1W
Application
SPV.01.1W
SPV.04.1W
SP1.01.1W
SP1.02.1W
SP2.02.1W
SP4.01.1W
SP4.03.1W
Unit 2: Activity 1
Level 1
Level 2
Level 3
Level 4
Student displays limited
knowledge of identified
concepts and
terminology
Student demonstrates
some knowledge of
identified concepts and
terminology
Student demonstrates
considerable
knowledge of identified
concepts and
terminology
Student exhibits
exceptional knowledge
of concepts,
terminology and/or
relationships
Demonstrates little
initiative in learning
terminology and
relationships
Demonstrates limited
initiative in learning
terminology and
relationships
Demonstrates
considerable initiative in
learning terminology
and relationships
Demonstrates
exceptional initiative in
learning terminology
and relationships
Only with constant
supervision, safely
assembles circuits
With occasional
supervision and
reminders, safely
assembles circuits
Safely and methodically
assembles circuits
Safely and methodically
assembles circuits
Demonstrates limited
initiative in
troubleshooting circuits
Demonstrates some
initiative in
troubleshooting circuits
Demonstrates
considerable initiative in
troubleshooting circuits
Demonstrates
considerable initiative in
troubleshooting circuits
Needs constant
supervision to follow
procedures
Needs supervision to
follow procedures but
improves
Follows procedures
independently and
accurately
Works efficiently and
independently, helps
others to work
efficiently
Student's report
demonstrates limited
clarity, knowledge of
facts or accurate
conclusions
Student reports
demonstrates some
accuracy and requires
some further effort to
communicate more
clearly
Student reports clearly
communicates the
ideas and issues and
demonstrates insightful
conclusions
Student communicates
meaningful information
with an exceptional
degree of clarity & with
a strong sense of
audience and purpose
Reports and diagrams
contain major heading
omissions, requires
rewrite
Reports and diagrams
contain minor
omissions, requires
some remedial work.
Considerable care in
producing reports and
diagrams, all elements
covered.
Exceptional care in
producing reports and
diagrams, contains
evidence of extra
research
Student works safely
and cleanly only with
constant supervision &
reminders
Student works safely &
cleanly with some
required supervision
Student works safely,
cooperatively & cleanly
with minimal
supervision and
demonstrates some
leadership skills
Student assists and
supervises others to
work safely & cleanly,
demonstrates
leadership skills
Demonstrates clear and
concise mathematical
and scientific reasoning
in reporting
Demonstrates initiative
in applying
mathematical and
scientific reasoning
throughout work
Requires further work in Requires more effort in
mathematical and
mathematical and
scientific reasoning
scientific reasoning in
reporting
- 31 -
TGJ3E (Microelectronics)
Accommodations
Strategies to accommodate the variety of learning styles in the classroom may include:
 additional handouts to illustrate discussion material;
 additional time allowance for completion of poster materials;
 flexibility in acceptable formats for presentations;
 additional research assignments;
 concentrated assistance with concept identification;
 additional one-on-one time by teacher or peer tutors;
 alternative activities to meet student needs;
 providing enrichment opportunities such as requirements for more in-depth research.
If required, consultations should be held with students, parents, resource, guidance and special
education departments when required to assist in creating an educational plan (IEP) for individual
students.
Resources
Simulation Software
Crocodile Clips
Spectrum Educational Supplies
125 Mary Street
Aurora, Ontario L4G 1G3
Phone: 905-727-6265
http://www.spectrumed.com
Electronic Workbench
111 Peter Street, Suite 801
Toronto, Ontario M5V 2H1
Phone: 416-977-5550 ext. 255
Books, Texts
 Mims, Forrest M. Engineer's Mini-Notebook, (series). Radio Shack/Archer, USA. 555 Timer IC
Circuits, 1984. Cat. 276-5010
 Petruzella, Frank D. Introduction to Electricity and Electronics. McGraw-Hill Ryerson, Toronto,
1986. ISBN 0-07-548899-X (Book 1), ISBN 0-07-548900-7 (Book 2)
Websites
Electronics for Beginnersourworld.compuserve.com/homepages/g_knott/
Alex’s Electronic Test Bench (glossary and resource catalog)- www.iserv.net/~alexx/index.htm
ePanorama, portal for everything electronicswww.us-epanorama.net/
Williamson Labs information on electronicswww.williamson-labs.com/home.htm
Unit 2: Activity 1
- 32 -
TGJ3E (Microelectronics)
Appendix 2.1.1: 555 Timer Design Brief
Title:
Project: The 555 Timer
Activity:
Design and build a timer
circuit for a variety of digital
and analog circuits
Time:
8 -10 hours
Communications Technology
Course: Grade 11 Workplace
Date:
RATIONALE
Many circuits including digital switches, timers, counters, light and sound effects generators
require a timing mechanism to produce a steady digital pulse. One of the time-honoured methods
uses a 555 IC, a linear IC that can be wired to produce a variety of pulses. Wiring a timer using
the 555 is a great project to learn about basic digital circuits, RC (resistor-capacitor) circuits, using
test instruments such as multimeters, capacitance meters and oscilloscopes, breadboarding and
troubleshooting, all skills that are required to develop more sophisticated electronics. This project
will lead to many devices used on future electronics projects.
THE ASSIGNMENT
Develop a timing circuit using the 555 timer IC. Use timing formulas to determine the frequency of
the circuit and test instrumentation to verify a working circuit.
LEARNING EXPECTATIONS: You will:
1.
2.
3.
4.
5.
design and construct electronic circuits using discreet components
test and verify operations of electronic circuits
calculate periods and frequencies using mathematical formula
use computer simulations to calculate circuit performance
write technical test reports
TOOLS AND MATERIALS
555 Timer handout
frequency counter
555 timer IC
mini-speakers
Unit 2: Activity 1
calculator
capacitance meter
variety of capacitors
power supply (9V battery
or bench supply)
- 33 -
multimeter
breadboard
resistors
simulation software
oscilloscope
alligator clips
LEDs
TGJ3E (Microelectronics)
EVALUATION
#
Deliverable
1
Test report
2
3
Completed circuits
Vocabulary test/report
TOTALS
#
periods
2
Mark
weighting (%)
40
5
2
9
40
20
100
Notes
Math calculations, diagrams,
test results, observations
Clean, precise work
NOTES
ALL CIRCUITS MUST BE INSPECTED BY TEACHER BEFORE POWER IS APPLIED
All reports must be word processed, diagrams or images to be created using illustration or CAD
software.
Each individual in a group or team must hand in their own reports.
WHEN IN DOUBT, ASK!
VOCABULARY
analog electronics
digital electronics
resistance/ohms
capacitance/Farads
capacitor
resistor
colour code (resistors)
voltage/volts
IC
555 timer
breadboard
voltmeter
ohmmeter
capacitance meter
frequency counter
oscilloscope
time base
signal
square wave
frequency/Hertz
period
pulse width
duty cycle
monostable and astable
multivibrators
switch debouncer
SI measurements: pico, micro,
milli, kilo, mega
PROJECT
STEP
1
2
STUDENT ACTIVITIES
Read the 555 Timer Project Handout and review circuit designs to become familiar with and note
the terminology, calculations and circuit diagrams. Calculate the pulse width or frequency of the
circuit you have been given. Retain all calculations and notes for the final report.
Obtain components, breadboard, etc. and build the circuit required. Obtain permission from the
instructor to apply power to circuit. Test and troubleshoot till you have a working circuit. SHOW
COMPLETE CIRCUIT FOR MARKING
3
Develop the test report and include circuit diagrams, calculations and results in an engineering test
report fashion. Include log sheets. Include vocabulary if required. HAND IN REPORT FOR
MARKING
4
Construct and test circuits based on the 555 and 556 timer ICs as given by your instructor.
Unit 2: Activity 1
- 34 -
TGJ3E (Microelectronics)
Appendix 2.1.2: 555 Timer Handbook
THE 555 TIMER PROJECT
Many devices, including clocks, timers, counters and even special effects generators require a source
of constant pulses to do their job. This can be accomplished with oscillators or timers...in which the
555 timer is a common example. The 555-timer chip can be used for a variety of projects which
require steady square pulses such as digital electronic mechanisms, timers, counters, switches,
flashers and sound effects generators.
The 555 Timer Project will introduce you to basic electronics: components such as resistors,
capacitors, diodes, ICs; breadboarding and wiring and measurement tools such as the multimeter, the
oscilloscope, the frequency counter and the capacitance meter. After completing this project you
should be ready to tackle the most complex circuits... it’s all down hill from here!
THE 555 TIMER
The timer can perform a variety of functions based on the circuitry surrounding it. It has 3 modes:
1. Monostable: “one-shot”, “pulse stretcher”; takes an analog signal such as a switch and produces
a clean square pulse. It is used in switch debouncing, required in digital electronics for example.
2. Bistable: can flip from one state (high/low, on/off,...etc.) to the other; not used in timing circuits or
from timer ICs.
3. Astable: “multivibrator”, “clock”, “square wave generator”; from input signal such as switch, will
constantly flip from one state to the other in sequence.
We will be building an astable circuit. 555s operate from +4.5 V to +18 V, with +9 V to +12 V the most
stable, however it is also great for +5 V TTL operations in digital electronics. We will concentrate on
+9 V, using a 9-V battery.
NOTES:
For critical timing, 1% tolerance resistors should be used. Use a variable resistor to tune resistances
if real critical. Capacitors generally have wide tolerances and plastic film is better. For capacitance
from 1uF to 10uF, use tantalums. Over 10uF may require electrolytic, which have wide tolerances.
Also note that the capacitor to ground on pin 5 is not required, but desirable for stability. A 0.01uF
capacitor is desirable.
THE 555 PINOUT (see diagram)
The 555 Timer IC is an 8 pin DIP. The pinouts are noted below:
Pin 1: GROUND
connected to ground (reference voltage)
Pin 2: TRIGGER
input, initiates timing sequence
Pin 3: OUTPUT
output of IC, connected to other devices
Pin 4: RESET
cancels current timing sequence
Pin 5: EXT. CONTROL
not generally used, can be used for external control voltages
Pin 6: THRESHOLD
sets internal switching point
Pin 7: DISCHARGE
discharges external capacitor, senses end of cycle
Pin 8: Vcc
positive voltage supply (+4.5 V to +18 V)
Unit 2: Activity 1
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TGJ3E (Microelectronics)
Notes:
Unit 2: Activity 1
- 36 -
TGJ3E (Microelectronics)
MONOSTABLE MODE (see diagram)
The monostable mode is useful for “cleaning up” a switch such as a push button or toggle.
These analog devices produce spikes which can produce unwanted effects. The monostable
timer takes the switch’s signal and produces a clean square output. The monostable 555
timer requires a capacitor and a resistor to set the pulse width. Note that the output is LOW
until triggered by a negative input pulse, then it will go HIGH with a length of pulse specified
by:
T=1.1(R1)(C1)
where R1 is in ohms and C1 is in Farads.
For example:
R1=22Kohms
C1=0.33µF
T=1.1(R1)(C1)
T=1.1 X 22000 Ω X 0.00000033 F
T=0.008s
T=8 ms
MONOSTABLE
EXAMPLES
Circuit 2
Circuit 3
Circuit 4
R1
C1
Pulse
100 K
470 K
1M
25µF
50µF
100µF
2.75 ms
25 s
110 s
This circuit can produce from pulse widths from about 10ms to the limits of R1 and C1. Try
ranges of R1 from 100 Ω to 13M Ω, 10K to 1M are the best for stability and reliability. C1
should be 100pF minimally to avoid stray capacitance, use capacitors in parallel to create
greater capacitance.
Unit 2: Activity 1
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TGJ3E (Microelectronics)
Notes:
Unit 2: Activity 1
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TGJ3E (Microelectronics)
ASTABLE MODE (see diagram)
The 555 can be used in an astable mode to create clock circuits, tone generators, frequency dividers,
light triggered timers, event failure alarms, etc. As the input goes HIGH, the output flips from HIGH
and LOW in a continuos cycle. Two time periods must be calculated: the HIGH time period and the
LOW time period, (the length of time it stays HIGH and LOW respectively). A complete cycle from
HIGH to LOW is known as the period (T).
TH = 0.693(C1)(R1 + R2)
TL = 0.693(C1)(R2)
TOTAL Period (T) = TH + TL
1
Frequency =
T(Hertz or Hz)
therefore:
Frequency =
EXAMPLE
ASTABLE
Circuit 1
Circuit 2
Circuit 3
1
[0.693(C1)(R1  2(R2))]
R1
R2
C1
Freq. (Hz)
470 K
470 K
2.2 K
470 K
470 K
4.7 K
0.22 µF
50 µF
0.01 µF
4.65 Hz
0.02 Hz
12 453 Hz
Note that increasing capacitance decreases frequency. Also note that if the LED stays “ON”, it may
that the frequency is too high for you to see the blinking. Try experimenting with different
combinations.
The DUTY CYCLE is the ratio of TH/T, and is an indication of the amount of time the cycle is HIGH
compared to LOW. A square wave would have a 50% duty cycle. Making the value of R1 very small
compared to R2 will produce a close square wave.
The upper limit of timing with a 555 timer is approximately 10-15 minutes. Cascading 555s or using
the dual timer (556) or quad timer (558) can provide longer timing sequences. Combining timers and
connecting speakers can produce a variety of sound effects generators. (Use a capacitor in series
with the speaker to protect it from DC voltages).
OTHER NOTES
Resistors:
devices that restrict electric flow and act as “taps”, controlling the amount of flow
(current) in a circuit. Is used to protect devices from high currents, direct current to
circuit pathways and divide voltage (electrical pressure) into different circuit pathways.
Measured in Ohms.
Capacitors:
devices that can store a charge, (negative and positive) and hence act as temporary
batteries. Caps are used as power storage; in series with resistors to change timing,
(by holding and then slowing the release of current); and are used as filters to absorb
low frequencies and pass on high frequencies. Capacitance in measured in Farads,
most commonly micro-Farads (uF) or pico-Farads (pF).
LED:
light emitting diode, emits light when forward biased.
Unit 2: Activity 1
- 39 -
TGJ3E (Microelectronics)
Notes:
Unit 2: Activity 1
- 40 -
TGJ3E (Microelectronics)
555 Timer Project: Some Notes Concerning Capacitors
Capacitors come in a wide variety of types, materials, sizes, shapes, labels, colour codes, etc. and
may be confusing for the beginning electronics student. They also come in fairly wide tolerances, so
the use of a capacitance meter is recommended. Capacitance is measured in Farads, usually in
microfarads (µF) or picofarads (pF). Capacitors also have a voltage rating, which is how much
voltage it can take, in practise half that number is used for the working voltage. Variable caps are
called trimmers.
A capacitor is constructed of two metal plates separated by an insulator called a dielectric. It stores
electrical energy by building up voltages on the metal plates (opposite charges). Dielectrics used are
air, mica, plastic, ceramic and metal oxide, and in the old days by oiled or waxed paper. The size of
the metal plates, the distance between them and the dielectric material determines how much charge
it can hold, called the capacitance. For large plates, they are rolled in cylinders to save space.
MICA CAPACITORS
high working voltages…determined by size, sealed against moisture, capacitance and tolerance
marked by colour dots
CERAMIC AND MYLAR
ceramic: disc or cylindrical shapes, mylar: “drop” shaped, colour code can be bands, or dots,
otherwise marked numerically
if whole number: picofarads, if decimal number: microfarads, Colour code always in picofarads,
tolerance may be marked by letter, not marked is +/- 20%
miniature capacitors may have picofarad value marked in three letter code; first two numbers are
digits followed by multiplier (or number of zeroes), i.e. 104Z
Tolerance
Letter
C
D
F
G
J
K
M
10 pF or LESS
(in +/- pF)
0.2
0.5
1.0
2.0
COLOUR
black
brown
red
orange
yellow
green
blue
violet
gray
white
OVER 10 pF
(in +/- %)
1
2
5
10
20
DIGITS
0
1
2
3
4
5
6
7
8
9
MULTIPLIER
1
10
100
1000
0.01
0.1
Tol. > 10pF, in %
20
1
2
Tol. < 10pF, in pF
2.0
5
0.5
10
0.25
1.0
ELECTROLYTIC CAPACITORS
usually greater than 1.0 µF, mostly polarized, .i.e., one lead is marked either negative or positive.
Must be connected with correct polarity. Values often marked, sometimes with MFD, meaning µF.
Unit 2: Activity 1
- 41 -
TGJ3E (Microelectronics)
Appendix 2.1.3: Engineering Test Report Format
All engineering test reports must include:
Overall
COVER SHEET, with:
company name and logo
project title
your name
team member names
class
date
EACH PAGE includes:
company name
class
date
Contents
PURPOSE OF PROJECT
DESCRIPTION OF PROJECT
include graphics, sketches, drawings, charts,
all graphics labeled and/or titled
METHODS
includes calculations
PROJECT RESULTS
PROJECT SYNOPSIS
analysis of results
what could be done better
how to improve next project results
how you could improve as a scientist or engineer
DAILY LOG
compiled from daily journal entries
hours worked on project
Unit 2: Activity 1
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TGJ3E (Microelectronics)
Appendix 2.1.4: ELECTRONIC INSTRUMENTATION PRIMER
Multimeter
Measures voltage (“electron pressure”) in Volts (V)
Measures resistance (the “flow control”) in Ohms
Measures current (“the flow”) in Amperes (A)
These three make up Ohm’s Law: V=IR (Voltage= current x resistance). NOTE: resistance must be
measured without power to the circuit, and current must be measured as part of the circuit: i.e.
electrons must flow the meter to be measured.
Capacitance Meter
Measures capacitance, the amount of static charge that can be stored in a capacitor. Capacitance is
measured in Farads, typically micro- or pico-Farads. (µF or pF)
Inductance Meter
Measures the amount of inductance, or reverse voltage generated by a coil or choke. Inductance is a
factor of electromagnetics and is measured in Henrys (H). Can be thought of resistance due to a
changing current/voltage.
Oscilloscope
Measures time varying signal, shows voltage change over time. Usually has 2 or more channels to
compare signals.
Frequency Counter
Counts pulses or signal peaks in a time varying signal
Function Generator
A function generator (or signal generator) supplies a test signal or waveform to test circuitry. It usually
can supply a square wave, (to test digital circuits), a sawtooth wave and a sine wave.
DC Power Supplies
DC Power Supplies supply clean direct current or steady voltage to the circuit, like a battery though
cleaner and more stable.
Electron Motion
Electronic devices operate by the movement of electrons through conductors, e.g. wires, and
electronic components. Electron parameters are described by the following basic quantities:
Charge
Symbol: q, unit: coulomb (C)
Charge is an amount of electrons. One coulomb is the charge of 6x1018 electrons.
Current
Symbol: I, unit: ampere or amp (A)
Current is the rate of flow of charge, i.e., the number of coulombs flowing past a point per second.
One amp is equal to one coulomb per second.
Unit 2: Activity 1
- 43 -
TGJ3E (Microelectronics)
Voltage
Symbol: V or E, unit: volt (V)
Voltage (also called potential, potential difference, potential drop, or electromotive force - EMF) is the
electronic potential energy between two points, and is the driving force that causes charge to flow.
One volt is defined as the potential difference that requires one joule of energy to move one coulomb
of charge. Voltage is always measured relative to some other point in a circuit, e.g., the potential
across a resistor. Voltage measurements made at a single point in a circuit are made relative to the
earth (ground), which is assigned an "absolute" voltage of zero.
Impedance
Symbol: Z, unit: ohm
Impedance is the degree to which an electronic component impedes the flow of current. In general it
is a frequency-dependent quantity. The impedance of a resistor is also called its resistance. The
impedance of capacitors and inductors is also called their reactance. Capacitors consist of a
dielectric material separating two parallel plates. They are used to hold charge or to transmit an ac
signal and block a dc signal.
Capacitance
Symbol: C, unit: farad (F)
Q = CV, I = C(dV/dt)
Capacitance is the amount of charge a capacitor can hold per volt.
The ability of a dielectric material between conductors to store electricity when a difference of
potential exists between the conductors. The unit of measurement is the Farad “F”, which is the
capacitance value that will store a charge of one Coulomb when a one volt potential difference exists
between the conductors. In AC, one Farad is the capacitance value which will permit one Ampere of
current when the voltage across the capacitor changes at a rate of one Volt per second.
Inductance
Symbol: L, unit: henry (H)
Inductance is ... V = L(dI/dt)
An inductor is a coil of wire that stores energy as a magnetic field. The coil is usually wrapped around
an iron-containing core, which increases the amount of energy that can be stored by the inductor.
Unit 2: Activity 1
- 44 -
TGJ3E (Microelectronics)
Audio Electronics: Signal Processing
Unit 2 Activity 2
800 minutes
Description
Students develop bridge rectifiers, filters, and transistor and/or operational amplifier (op-amp)
amplifiers to condition and amplify audio level signals. Through this activity, students learn the basics
of semiconductors and their applications, as well as processing electromagnetic signals. This activity
leads into Activity 3: Project Loudspeaker, in which audio signals are filtered and used to power
speaker systems.
Strands and Expectations:
Strand
Theory and Foundation
Skills and Processes
Impact and Consequences
Overall
Specific
TF2.05.1W
TF2.14.1W
TF2.10.1W
TVF.02.1W
TF3.01.1W
TF2.12.1W
TF3.02.1W
TF2.13.1W
SP1.01.1W
SP2.05.1W
SP1.02.1W
SP2.06.1W
SPV.01.1W
SP1.03.1W
SP3.01.1W
SPV.02.1W
SP2.01.1W
SP4.01.1W
SPV.04.1W
SP2.02.1W
SP4.02.1W
SP2.04.1W
SP4.03.1W
IC2.01.1W
See Appendix E for full description of TGJ3E expectations
HRDC NOC Specialized Skills
2133
2241
2242
2243
2244
7245
7246
Electrical and electronics engineers
2133.1.1
2133.1.3
2133.1.4
2133.1.6
Electrical and electronics engineering technologists and technicians
Technologists:2241.1.1
2241.1.2
2241.1.3 2
241.1.4
2241.1.5
2241.1.6
Technicians: 2241.2.1
2241.2.2
2241.2.4
2241.2.5
2241.2.6
2241.2.7
2241.2.8
Electronic service technicians (household and business equipment)
2242.1.1
2242.1.2
2242.1.3
2242.1.4
2242.1.5
Industrial instrument technicians and mechanics
2243.1.2
2243.1.3
2243.1.4
Aircraft instrument, electrical and avionics mechanics, technicians and inspectors
Aircraft Instrument Mechanics and Technicians
2244.1.1
2244.1.2
Avionics Mechanics and Technicians
2244.2.1
Telecommunications line and cable workers
7245.1.4
7245.1.5
Telecommunications installation and repair workers
Telephone Installers and Repairers
7246.1.1
Switch Network Installers and Repairers
7246.2.1
7246.2.2
7246.2.3
Telecommunications Service Testers
7246.3.2
7246.3.4
7246.3.5
Telecommunications Equipment Technicians
7246.4.2
7246.4.3
Unit 2: Activity 2
- 45 -
TGJ3E (Microelectronics)
7247
Cable television service and maintenance technicians
Cable Television Service Technicians
7247.1.3
Cable Television Maintenance Technicians 7247.2.3
Electric appliance servicers and repairers
Small Appliance Repairers 7332.1.3
7332.1.4
Major Appliance Repairers/Technicians
7332.2.3
7332.2.4
7332.2.5
Electronics assemblers, fabricators, inspectors and testers
Assemblers 9483.1.1
9483.1.3
Inspectors
9483.3.1
9483.3.4
9483.3.5
Testers
9483.4.1
9483.4.3
9483.4.5
Assemblers and inspectors, electrical appliance, apparatus and equipment manufacturing
Assemblers 9484.1.6
Inspectors and Testers
9484.2.1
9484.2.1
See Appendix F for full description of NOC Specialized Skills
7332
9483
9484
HRDC NOC Essential Skills


reading
decision making


job-task planning
numeracy
 problem solving
 working withothers
See Appendix A for Essential Skill rubrics
Prior Knowledge
The test bench established in Unit 1 and equipment setup as in Unit 2: Activity 1 will be used in this
activity. Prior knowledge includes:
 basic test equipment identification and associated terminology;
 basic safety procedures, (but should be reviewed in any case);
 prototyping circuits from schematics;
 schematic symbols of basic components;
 simple algebraic equation manipulation;
 simple graphic and report production techniques.
Planning Notes
In addition to the equipment and supplies listed in Unit 2: Activity 1, the following items are required:
 assorted diodes, transistors, op-amps
 capacitance meter
 relays, SCR's etc. if required for specific
 4 ohm/8 ohm speakers
projects
 AC step down transformers, (optional)
 microphones (for amplifier input, optional)  silicone wafers (for demonstration)
 sound level meter (optional)
There is a wide variety of amplifier circuits available. Teachers may choose to purchase kits (such as
a 1W audio amplifier) to allow students to quickly practise signal processing and measurement
techniques. See the end of this activity for examples, and Resources for sources of kits and
components.
Other resources necessary for this activity include:
 teacher-developed handout detailing assignment requirements, (Appendix 2.2.1);
 handout detailing schematic circuits for amplifiers, etc. (Appendix 2.2.2)
 handout detailing test report format (see Appendix 2.1.3 in previous activity)
 sample working prototype circuits (optional)
Unit 2: Activity 2
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TGJ3E (Microelectronics)
The P-N junction, diode and transistor theories are covered in this activity. While some theory should
be discussed before initiating circuit breadboarding, most semiconductor component and circuit
basics are discussed in the context of solving a specified 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, then allow time for students to apply this knowledge to the
task of circuit building.
Teaching / Learning Strategies
This activity connects from Unit 2: Activity 1- The 555 Timer. Teachers may elect to establish new
groups or teams for this activity or retain groups from the previous activity.
Audio Electronic Communications
Teachers initiate discussions related to the audio frequency portion of the electromagnetic spectrum
(20Hz to 20MHz), continuing from Unit 2: Activity 1. Teachers should set-up a frequency generator,
oscilloscope and loudspeaker to illustrate the sound associated with frequency to give students a
sense of the audio spectrum. During the demonstration, teachers should point out the controls of the
oscilloscope and function generator.
Teachers discuss the propagation of sound from source to home or car receivers. Teachers can use
illustrations, physical equipment or a combination to highlight key concepts. Teachers should discuss
the following concepts:
 audio spectrum characteristics (decibel scale)
 signal filtering, (concepts of attenuation, low pass, band pass and high pass of signal strength)
 RF propagation through antennas, (how signals are broadcast through the air)
 electromagnetic signal receiving (how antennas pick up and receive energy, problems in
reception)
 transformation of electrical energy to mechanical reproduction in loudspeakers (parts of the
electromagnetic speaker, operation of an electromagnetic coil)
Students are then asked to develop one or more of the above concepts in a short research report,
including sketches or illustrations.
Rectifiers and Diodes
Teachers demonstrate amplitude and frequency modulation of sine waves. Teachers then
demonstrate a half-wave rectifier to initiate investigations into the diode and the PN junction.
Teachers can use the example of the LED to illustrate diode action. If time permits, a simple
demonstration of a seven-segment display may also be used.
Students then construct a full-wave rectifier using discrete diodes. Note: teachers may elect to rectify
stepped-down AC power sine waves, and discuss transformers and their operation at this time.
Capacitors are re-introduced (from Unit 2: Activity 1) for their function of filtering ripples. Students
complete circuits and develop graphs showing the following:
1. unprocessed sine wave;
2. sine wave through half rectifier;
3. sine wave through full rectifier;
4. sine wave through full rectifier and capacitor filter;
5. sine wave through full rectifier and capacitor-choke filter (optional).
Unit 2: Activity 2
- 47 -
TGJ3E (Microelectronics)
At this point, teachers may decide to have students construct a 5V regulated power supply from 60Hz
AC. (optional task)
Bipolar and FET Transistor Amplifiers
Teachers continue discussion of semiconductors by extending discussions on the PN junction to the
PNP and NPN junction. The properties of a transistor to act as a solid state switch and an amplifier of
small signals is illustrated by constructing simple circuits and demonstrating the signals on the
oscilloscope.
Students are then given circuit diagrams of basic transistor amplifiers to construct and produce a final
presentation of their circuit work. Students are asked to produce a final report on their completed
circuits.
Op-Amp Amplifier
Linear IC op amps are useful to demonstrate sound amplification. Teachers discuss a circuit diagram
of a typical 741 or 380 op amp (perhaps using microphone input), and ask students to construct an
inverted amplifier or voltage comparator. Students demonstrate their circuits to the class and
complete a simple report on the results of their circuit testing.
Students to hand in a vocabulary list or write a formal test:
Vocabulary
Students should be able to define the following terms, components and/or processes:
 audio frequency
 semiconductor
 PN Junction
 diode
 forward bias
 reverse bias
 LED
 zener voltage
 seven-segment display
 transistor
 emitter/collector/base
 NPN/PNP
 current gain
 heat sink
 RF
 AM/FM
 rectifier
 transformer
 half-wave rectifier
 full-wave rectifier
 inductance
 filter
 choke
 waveform
 cathode
 anode
 amplifier
 integrated circuit
 linear IC
 Op amp
 comparator
Assessment / Evaluation
Students will be assessed and evaluated on several aspects of this project;
 functional quality of circuits (clean and detailed work, safe procedures)
 Test Report on circuits (initiative, depth of content, presentation, originality)
 presentation (demonstration of depth of knowledge and research)
Unit 2: Activity 2
- 48 -
TGJ3E (Microelectronics)
Assessment Rubric for Circuit Report, Diagrams and Presentation
Criteria
Students will:
Knowledge
TVF.02.1W
TF2.05.1W
TF2.10.1W
TF2.12.1W
TF2.13.1W
TF2.14.1W
Inquiry
SPV.01.1W
Communication
SP1.03.1W
SP2.01.1W
SP4.01.1W
SP4.02.1W
Application
SPV.04.1W
SP1.01.1W
SP1.02.1W
SP2.02.1W
SP4.01.1W
SP4.03.1W
Unit 2: Activity 2
Level 1
Student displays
limited initiative in
demonstrating
knowledge of
identified equipment
concepts,
terminology and
symbols; may be
missing important
elements
Missing some
important details on
communication
systems as
prescribed
Demonstrates some
knowledge of safe
handling of
troubleshooting
procedures but
requires constant
remedial help in
following instructions
Report and
presentation
demonstrates limited
clarity of information,
knowledge of
vocabulary basics
Demonstrates some
knowledge into
scientific and
mathematical
principles but
requires remediation
in important details
Level 2
Level 3
Student
demonstrates some
adequate initiative in
demonstrating
knowledge of
identified equipment
concepts,
terminology and
symbols; may be
missing minor
elements
Missing minor details
of communications
systems as
prescribed
Student
demonstrates
considerable initiative
in demonstrating
knowledge of
identified concepts,
terminology and
symbols; no missing
required elements
Student exhibits
exceptional initiative
and depth in
demonstrating
knowledge of
identified concepts,
terminology and
symbols; shows
evidence of further
research
Demonstrates
knowledge of
communications
systems as
prescribed
Demonstrates
extensive knowledge
of communications
systems beyond
those prescribed
Demonstrates safe
handling of
troubleshooting
procedures, but
requires remedial
help in following
instructions
Demonstrates
thorough and safe
handling of
troubleshooting
procedures
Demonstrates ability
to assist others in
following safe and
thorough testing and
troubleshooting
procedures
Report and
presentation
demonstrates
adequate clarity of
information (may
have some content
and/or formatting
errors requiring
remediation);
adequate or basic
knowledge of
vocabulary
demonstrated
Demonstrates
adequate knowledge
into scientific and
mathematical
principles
but may require
some remediation in
minor details
Report and
presentation clearly
communicates all
required concepts
and ideas,
demonstrates
knowledgeable
vocabulary
Report and
presentation
creatively
communicates
meaningful
information with an
exceptional degree of
clarity beyond
required elements
Demonstrates
working knowledge
into scientific and
mathematical
principles
Demonstrates
additional research
into scientific and
mathematical
principles
- 49 -
Level 4
TGJ3E (Microelectronics)
Assessment Rubric for Circuit Building
Criteria
Students will:
Knowledge
TVF.02.1W
TF2.10.1W
TF3.01.1W
TF3.02.1W
Inquiry
SPV.02.1W
SP2.04.1W
SP2.05.1W
SP2.06.1W
Communication
SP1.03.1W
SP2.01.1W
Application
SPV.01.1W
SPV.04.1W
SP1.01.1W
SP1.02.1W
SP2.02.1W
SP4.01.1W
SP4.03.1W
IC2.01.1W
Unit 2: Activity 2
Level 1
Level 2
Level 3
Level 4
Demonstrates
understanding of only
some key terms,
component functions
Demonstrates
understanding of most
key terms, component
functions
Demonstrates
understanding of all key
terms, component
functions and unit
values
Demonstrates thorough
and comprehensive
understanding of all
terminology;
component functions
and unit values
Student displays limited
initiative in proper use
of terminology and
symbols, demonstrating
knowledge of identified
concepts and
techniques
Student demonstrates
some adequate
initiative in proper use
of terminology and
symbols, demonstrating
knowledge of identified
concepts and
techniques
Student demonstrates
considerable initiative in
proper use of
terminology and
symbols, demonstrating
knowledge of identified
concepts and
techniques
Student exhibits
exceptional initiative in
use of terminology and
symbols and
demonstrating
knowledge of identified
concepts and
techniques
Demonstrates proper
and safe use of testing
equipment with some
important exceptions
Demonstrates proper
and safe use of testing
equipment with minor
exceptions
Demonstrates proper
and safe use of testing
equipment as required
Demonstrates some
knowledge of safe
handling of testing,
troubleshooting and
recording procedures
but requires constant
remedial help in
following instructions
Demonstrates safe
handling of testing,
troubleshooting and
recording procedures,
but requires remedial
help in following
instructions
Demonstrates thorough
and safe handling of
testing, troubleshooting
and recording
procedures
Establishes exceptional
clean and safe use of
testing equipment
beyond normal
requirements
Demonstrates ability to
assist others in
following safe and
thorough testing,
troubleshooting and
recording procedures
Test report requires
important remedial
work; contains missing
elements or errors,
limited documentation
of process
Test report requires
minimal remedial work;
contains some minor
missing elements or
errors, mostly accurate
documentation of
process
Test report is clear and
contains all required
elements without error,
accurate
documentation of
process
Test report contains
researched elements
beyond requirements;
demonstrates
professional level work
& effort, accurate
documentation of
process
Requires constant
prodding to work with
colleagues in
completing assignment
Requires some minimal
prodding to work with
colleagues in
completing assignment
Works well with
colleagues in
completing assignment
Goes out of way to
assist others in
completing
assignments
Displays some major
errors in measurement
techniques or
calculations
Demonstrates some
trouble in identifying
important hazards and
demonstrates proper
safety procedures with
a high level of
supervision required
Displays minimal errors
in measurement
techniques and/or
calculations
Can identify all
important hazards and
demonstrates proper
safety procedures with
a low level of
supervision required
Displays correct
measurement
techniques and
calculations
Can identify all hazards
and demonstrates
proper safety
procedures at all times
Advanced knowledge of
measurement
techniques and
precision calculations
Can identify all general
and specific hazards
and demonstrates a
thoroughness in
applying proper safety
procedures at all times,
including before and
after class
- 50 -
TGJ3E (Microelectronics)
Accommodations
Teachers must use discretion in the depth of project material covered in this activity. There are plenty
of circuit designs that can be developed for more advanced students, or teachers may elect to limit
the amount of circuits to be built. All students should be able to demonstrate knowledge and skills in
audio physics and sound reproduction technology.
Strategies to accommodate the variety of learning styles in the classroom may include:
 additional handouts such as drawings, terminology sheets, circuit designs, pictorial drawings,
use of simulation labs to facilitate input;
 additional time allowance for completion of reports;
 flexibility in acceptable formats for reports;
 additional one-on-one time by teacher or peer tutors;
 concentrated one-on-one assistance in hands-on activities;
 additional research assignments;
 alternative activities to meet student needs;
 providing enrichment opportunities such as requirements for more in-depth research;
 additional responsibilities such as project or facility managers.
Resources
Suppliers
ABRA Electronics Corp.
5787 Pare
Montreal, Que. H4P 1S1
1-800-361-5237
Fax 514-731-0154
sales@abra-electronics.com
Addison Electronics Ltd.
8018, 20e Avenue
Montreal, P.Q. H1Z 3S7
Tel: 514-376-1740
Radio Shack
(see local phone book)
Electrolab Training Systems
Belleville
http://www.elabonline.com
Active Surplus
345 Queen Street W.
Toronto, Ontario M5V 2A4
1-800-465-KITS
Books, Texts
Petruzella, Frank D. Introduction to Electricity and Electronics. McGraw-Hill Ryerson, Toronto, 1986.
ISBN 0-07-548899-X (Book 1), ISBN 0-07-548900-7 (Book 2)
Websites
Alex’s Electronic Test Bench (glossary and resource catalog)www.iserv.net/~alexx/index.htm
Electronics for Beginnersourworld.compuserve.com/homepages/g_knott/
ePanorama, portal for everything electronicswww.us-epanorama.net/
Williamson Labs information on electronicswww.williamson-labs.com/home.htm
Unit 2: Activity 2
- 51 -
TGJ3E (Microelectronics)
Appendix 2.2.1: Audio Amplifier Design Brief
Title:
Project: The Audio Amplifier
Activity:
Design and build an audio amplifier
to amplify small signals
Course:
Time:
8 -10 hours
Date:
Communications Technology
Grade 11 Workplace
RATIONALE
In any electronic-based communications product, small signals delivered through cable or antennas
need to be amplified in order to drive speakers. By utilizing transistors and/or operational amplifier
(op amp) devices, you will design and develop a circuit that will take a small signal and amplify the
signal to drive speakers. This project helps you understand the uses and function of semi-conductor
devices. You will use this knowledge to design and build sound systems for a variety of uses.
THE ASSIGNMENT
Develop a diode rectifier, as well as a transistor and/or op amp signal amplifier.
LEARNING EXPECTATIONS: You will:




design and construct electronic circuits using discreet components
test and verify operations of electronic circuits
calculate periods and frequencies using mathematical formula
write technical test reports
TOOLS AND MATERIALS
 amplifier circuit

diagrams

 frequency counter

 resistors

 op amps (741 or
380)
Unit 2: Activity 2
calculator
capacitance meter
LEDs
mini-speakers
- 52 -




multimeter
breadboard
diodes
power supply (9V
battery or bench
supply)
 oscilloscope
 variety of
capacitors
 transistors
 simulation software
TGJ3E (Microelectronics)
EVALUATION
(periods)
Mark
weighting (%)
Test report
2
20
Completed circuits
presentation
Vocabulary test/report
TOTALS
4
2
2
10
30
30
20
100
#
Time
Deliverable
1
2
3
4
Notes
Math calculations, diagrams,
test results, observations
Clean, precise work
Knowledge of facts
NOTES
ALL CIRCUITS MUST BE INSPECTED BY TEACHER BEFORE POWER IS APPLIED
All reports must be word processed, diagrams or images to be created using illustration or CAD
software.
Each individual in a group or team must hand in their own reports.
WHEN IN DOUBT, ASK!
VOCABULARY
 audio frequency
 semiconductor
 PN Junction
 diode
 forward bias
 reverse bias
 LED
 Zener voltage
 seven-segment display
 transistor











emitter/collector/base
NPN/PNP
current gain
heat sink
RF
AM/FM
rectifier
transformer
half-wave rectifier
full-wave rectifier
inductance










filter
choke
waveform
cathode
anode
amplifier
integrated circuit
linear IC
Op amp
comparator
PROJECT
STEP STUDENT ACTIVITIES
1
Review the circuit diagrams and collect the necessary parts. Retain all calculations and
notes for the final report.
2
Obtain components, breadboard, etc. and build the circuit required. Obtain permission
from the instructor to apply power to circuit. Test and troubleshoot till you have a working
circuit. SHOW COMPLETE CIRCUIT FOR EVALUATION.
3
Present your circuit to the class. Develop the test report and include circuit diagrams,
calculations and results in an engineering test report fashion. Include log sheets. Include
vocabulary if required. HAND IN REPORT FOR EVALUATION.
4
Construct and test circuits based on transistor and op amp as given by your instructor.
Unit 2: Activity 2
- 53 -
TGJ3E (Microelectronics)
Appendix 2.2.2: 1-WATT AMPLIFIER- example circuit
PARTS LIST
 R/1
 R/2
 R/3
 R/4
 R/5
 R/6
 R/7
 R/8
 R/9
 R/10
 R/11
 R/12
 C/1
 C/2
Unit 2: Activity 2













4.7 Meg ohm Resistor
2.7 Meg ohm Resistor
33 ohm Resistor
1 K ohm Resistor
4.7 meg ohm Resistor
1.8 K ohm Resistor
3.9 ohm Resistor
10 ohm Resistor
10 ohm Resistor
10 ohm Resistor
560 ohm Resistor
22 ohm Resistor
0.22 uf Capacitor
0.22 uf Capacitor
- 54 -
C/3
C/4
C/5
C/6
D/1
P/1
Q/1
Q/2
Q/3
Q/4
Q/5
W/1
SP/1
33 uf Electrolytic Capacitor
0.022 uf Capacitor
220 uf Electrolytic Capacitor
0.068 uf Capacitor
1N 4148 Diode
Trim Pot
2N 4401 NPN Transistor
2N 4401 NPN Transistor
2N 4403 PNP Transistor
2N 4401 NPN Transistor
2N 4403 PNP Transistor
Speaker Wire
Speaker
TGJ3E (Microelectronics)
Appendix 2.2.2: OP AMP AMPLIFIER- example circuit
CIRCUIT NOTES
 R2 controls 741 preamplifier
 R3 controls speaker volume
 Use a fixed 100k resistor for R2 if circuit oscillates or gives distorted output
 Important: filter power supply connections with 0.1uf capacitors
Unit 2: Activity 2
- 55 -
TGJ3E (Microelectronics)
Audio Electronics: Project Loudspeaker
Unit 2 Activity 3
1200 minutes
Description
Students design and construct a discreet component loudspeaker system with filter circuits,
(crossover network). Through the design, construction and testing of filtered signal circuits, students
gain an understanding of the principles of inductance, capacitance, electromagnetism, signal
manipulation, sound frequency and sound reproduction in a communication system.
Strands and Expectations
Strand
Theory and Foundation
Skills and Processes
Overall
TVF.02.1W
TVF.03.1W
SPV.01.1W
SPV.02.1W
SPV.04.1W
Specific
TF2.05.1W
TF2.10.1W
TF3.01.1W
TF2.12.1W
TF3.02.1W
TF2.13.1W
SP1.01.1W
SP2.05.1W
SP1.02.1W
SP2.06.1W
SP1.03.1W
SP3.01.1W
SP2.01.1W
SP4.01.1W
SP2.02.1W
SP4.02.1W
SP2.04.1W
SP4.03.1W
Impact and Consequences
See Appendix E for full description of TGJ3E expectations
HRDC NOC Specialized Skills
2133
2241
9483
2242
2243
9484
7332
7246
7245
7247
Electrical and electronics engineers
2133.1.2
2133.1.3
2133.1.6
Electrical and electronics engineering technologists and technicians
Technologists: 2241.1.1
2241.1.3
2241.1.5
2241.1.6
Technicians: 2241.2.1
2241.2.2
2241.2.4
2241.2.5
2241.2.6
2241.2.8
Electronics assemblers, fabricators, inspectors and testers
Testers
9483.4.1
9483.4.5
Electronic service technicians (household and business equipment)
2242.1.1
2242.1.2
2242.1.3
2242.1.4
2242.1.5
Industrial instrument technicians and mechanics
2243.1.2
2243.1.3
2243.1.4
Assemblers and inspectors, electrical appliance, apparatus and equipment manufacturing
Inspectors and Testers
9484.2.1
9484.2.1
Electric appliance servicers and repairers
Small Appliance Repairers 7332.1.3
Major Appliance Repairers/Technicians
7332.2.3
7332.2.5
Telecommunications installation and repair workers
Telecommunications Service Testers
7246.3.4
7246.3.5
Telecommunications Equipment Technicians
7246.4.2
Telecommunications line and cable workers
7245.1.4
7245.1.5
Cable television service and maintenance technicians
Cable Television Service Technicians
7247.1.3
Cable Television Maintenance Technicians 7247.2.3
See Appendix F for full description of NOC Specialized Skills
Unit 2: Activity 3
- 56 -
TGJ3E (Microelectronics)
HRDC NOC Essential Skills


problem solving
job-task planning


computer use
finding information
 decision making
 numeracy
See Appendix A for Essential Skill rubrics
Prior Knowledge
Students learn the basics of the electromagnetic spectrum in Activity 2. Prior knowledge therefore
includes:
 Basic test equipment identification and associated terminology
 Basic safety procedures, (but should be reviewed in any case)
 Prototyping circuits from schematics
 Schematic symbols of basic components
 Simple algebraic equation manipulation
 Simple graphic and report production techniques
 Basic terminology of sound and electromagnetism
Planning Notes
This activity concentrates on the electronics behind the electromagnetic loudspeaker system. The
project may lead into the actual construction of a loudspeaker enclosure, or may be restricted to using
a prefabricated test box. Considerations before beginning this activity are:
 Constructing a loudspeaker enclosure entails a lengthy time allotment, (much more than
allocated here), the use of a wood shop facility, a trained wood shop instructor, the materials
and associated additional costs. Such an undertaking does take time and effort, and teachers
may feel that it takes too much away from the rest of the course.
 Used commercial loudspeakers may be used, and therefore the activity would involve
refurbishing the sound quality through the design and installation of a new crossover network.
Optionally, kits may be purchased that would shorten the time and fund requirements.
 Students may be attracted to the program through this activity, and may want to have speaker
systems built for their own use. Additionally, this activity could be used as a basis for a school
or community project, or for a special event funding drive. You may decide to run this activity
as a culminating performance task at the end of the semester.
 The expectations assessed and evaluated through this activity can be met through limiting the
activity to the design and construction of the electronic circuits for pre-existing loudspeaker
systems.
 A strategy to accomplish this project might be to develop a loudspeaker enclosure in an initial
semester, then use that enclosure as a test system for following semesters.
 Alternatively, the design and construction of the enclosure or a set of test boxes may be
accomplished in another course, such as Technological Design, Construction or
Manufacturing in concert with the Communications Team.
The specific equipment and supplies required are:
 Component speakers such as tweeters, midranges, woofers, subwoofers
 Assorted chokes, capacitors, diodes, L-pads, fuses, speaker wire
 Breadboards, jumpers, perf boards, soldering stations
 Test bench instrumentation for audio spectrum signals
 sound level meter (optional)
 sound spectrum analyzer (optional)
 audio test CD or cassette (optional)
 enclosure or enclosure material if constructing speaker systems
Unit 2: Activity 3
- 57 -
TGJ3E (Microelectronics)
Other resources necessary for this activity include:
 teacher-developed handout detailing assignment requirements, (Appendix 2.3.1);
 handouts/overheads detailing electromagnetic speaker parts and schematic circuits for
crossover circuits, etc. (Appendix 2.3.2)
 handout detailing test report format (see Appendix 2.1.3 from previous activity)
 sample crossover networks (optional, from Addisons, Radio Shack, etc….see Resources)
Teaching / Learning Strategies
Loudspeaker Design
Teachers assemble a range of components including:
 Tweeter
 Midrange
 Woofer
 Subwoofer (optional)
 Dual cone car speaker (optional)
 Crossover network (best: multi-tap)
Referring to Appendix 2.3.1, teachers initiate discussion about the types of electrodynamic speakers.
Teachers ask students to identify the obvious physical characteristics of the tweeter, midrange and
woofer. Teachers discuss the physics behind sound reproduction, including electrodynamics, power
vs. frequency, measuring sound with decibel scale, etc. Discussions are also initiated about
frequency response, damping, distortion, power rating, impedance and dispersion.
Students are asked to take notes during discussions; teacher may provide forms with spaces to fill
information to direct note taking. It is important to show students the physical speakers, in order for
them to appreciate the concepts. If possible, the teacher may want to drive an old speaker through
the audio spectrum to distortion to illustrate cone travel, clipping, power requirements to push air, etc.
Sound Physics
Teachers should reinforce earlier discussions on the audio spectrum. It would be instructive to use an
audio test CD or frequency generator capable of 20Hz to 20MHz to drive types of speakers to
illustrate frequency and amplitude concepts. The decibel scale is discussed. A sound-level meter
would be useful here to demonstrate sound levels. An oscilloscope should be used to visually
demonstrate changes in frequency. This topic leads into a demonstration of filter circuits.
Filter circuits
The concepts of crossover networks are addressed through a discussion and demonstration of the
effects of passing a range of frequencies through a choke and a capacitor. Teachers describe the
physics of what these components do to attenuate signals. Teachers demonstrate how to calculate
component values to determine frequency cut-off values. (See Appendix 2.3.2) Students
demonstrate signal attenuation with components, oscilloscope and function generators. Teachers
give students various components and ask them to calculate cutoff frequencies, and demonstrate
them on the test bench.
The orders of filter circuits are discussed and illustrated. Students are given a Design Brief to develop
various filter circuits, (see Appendix 2.3.1). Students are then asked to develop a test report,
evaluating what they have learned, and illustrating circuit diagrams.
Enclosures
Teachers discuss the terminology of speaker enclosure types, demonstrating enclosure types.
At this point, teachers either work to build a set of speaker enclosures, or else continue with
constructing crossovers for existing speakers
Unit 2: Activity 3
- 58 -
TGJ3E (Microelectronics)
Constructing Crossovers
Students are given specific frequency cutoff points and are asked to develop and test their circuit.
Teachers evaluate student knowledge and skills in their circuit design. Once appraised, students build
their circuit on perf board or equivalent. Students assemble and test the speaker system.
Assessment/Evaluation
Students will be assessed and evaluated on several aspects of this project;
 functional quality of circuits (clean and detailed work, safe procedures)
 Test Report on circuits (initiative, depth of content, presentation, originality)
 Presentation (demonstration of depth of knowledge and research)
Assessment Rubric for Project Loudspeaker
Expectations
Students will:
Knowledge
TVF.02.1W
TVF.03.1W
TF2.05.1W
TF2.10.1W
TF2.12.1W
TF2.13.1W
TF3.01.1W
TF3.02.1W
Inquiry
SPV.01.1W
SPV.02.1W
SP2.04.1W
SP2.05.1W
Communication
SP1.03.1W
SP2.01.1W
SP3.01.1W
SP4.01.1W
SP4.02.1W
Unit 2: Activity 3
Level 1
Level 2
Level 3
Level 4
Student displays limited
initiative in
demonstrating
knowledge of identified
equipment concepts,
terminology and
symbols; may be
missing important
elements
Student demonstrates
some adequate
initiative in
demonstrating
knowledge of identified
equipment concepts,
terminology and
symbols; may be
missing minor elements
Student demonstrates
considerable initiative in
demonstrating
knowledge of identified
concepts, terminology
and symbols; no
missing required
elements
Student exhibits
exceptional initiative
and depth in
demonstrating
knowledge of identified
concepts, terminology
and symbols; shows
evidence of further
research
Student displays limited
initiative in proper use
of terminology and
symbols, demonstrating
knowledge of identified
concepts and
techniques
Student demonstrates
some adequate
initiative in proper use
of terminology and
symbols, demonstrating
knowledge of identified
concepts and
techniques
Student demonstrates
considerable initiative in
proper use of
terminology and
symbols, demonstrating
knowledge of identified
concepts and
techniques
Student exhibits
exceptional initiative in
use of terminology and
symbols and
demonstrating
knowledge of identified
concepts and
techniques
Demonstrates proper
and safe use of testing
equipment with some
important exceptions
Demonstrates proper
and safe use of testing
equipment with minor
exceptions
Demonstrates proper
and safe use of testing
equipment as required
Establishes exceptional
clean and safe use of
testing equipment
beyond normal
requirements
Demonstrates some
knowledge of safe
handling of testing,
troubleshooting and
recording procedures
but requires constant
remedial help in
following instructions
Demonstrates safe
handling of testing,
troubleshooting and
recording procedures,
but requires remedial
help in following
instructions
Demonstrates thorough
and safe handling of
testing, troubleshooting
and recording
procedures
Demonstrates ability to
assist others in
following safe and
thorough testing,
troubleshooting and
recording procedures
Report demonstrates
limited clarity of
information, knowledge
of vocabulary basics
Report demonstrates
adequate clarity of
information (content
and/or formatting errors
requiring remediation);
adequate or basic
knowledge of
vocabulary shown
Report clearly
communicates all
required concepts and
ideas, demonstrates
knowledgeable
vocabulary
Report creatively
communicates
meaningful information
with an exceptional
degree of clarity
beyond required
elements
- 59 -
TGJ3E (Microelectronics)
Project Loudspeaker rubric cont’d
Application
SPV.04.1W
SP1.01.1W
SP1.02.1W
SP2.02.1W
SP2.06.1W
SP4.01.1W
SP4.03.1W
Demonstrates some
knowledge into
scientific and
mathematical principles
but requires
remediation in
important details
Demonstrates
adequate knowledge
into scientific and
mathematical principles
but may require some
remediation in minor
details
Demonstrates working
knowledge into
scientific and
mathematical principles
Demonstrates
additional research into
scientific and
mathematical principles
Requires constant
supervision, but does
accomplish task in time
allotted
Requires some
supervision in order to
stay on task but does
accomplish goals in
time frame allotment
Keeps on task until
completion, assists
others on team to
accomplish goals
Demonstrates efficient
use of time, organizes
work team to
accomplish goals
Accommodations
Teachers must determine the capabilities of their classrooms and use discretion in the depth of
project material covered in this activity. Teachers may elect to limit the task to crossover network
design and development, or extend the activity to design and build the entire system. All students
should be able to demonstrate the knowledge and skills in audio physics and sound reproduction
technology.
Strategies to accommodate the variety of learning styles in the classroom may include:
 additional handouts such as drawings, terminology sheets, circuit designs, pictorial drawings,
use of simulation labs to facilitate input;
 additional time allowance for completion of reports;
 flexibility in acceptable formats for reports;
 additional one-on-one time by teacher or peer tutors;
 concentrated one-on-one assistance in hands-on activities;
 additional research assignments;
 alternative activities to meet student needs;
 providing enrichment opportunities such as requirements for more in-depth research;
 additional responsibilities such as project or facility managers.
Resources
Kits, Magazines, etc.
Old Colony Sound Labs
PO Box 243
Peterborough, NH 03458-0243
http://www.audioxpress.com/index1.htm
Suppliers
Shopkit Industries (speaker kits)
P.O Box 1573
Superior, Wisconsin USA 54880
Al Olson
ph. 1-800-236-4429
ph. 1-715-392-5522
http://www.cpinternet.com/~shopkit
Unit 2: Activity 3
Speaker Builder Magazine
PO Box 494, Dept LDC5
Peterborough, NH 03458-0494
http://www.audioxpress.com/magsdirx/spkrbldr/
ABRA Electronics Corp.
5787 Pare
Montreal, Que H4P 1S1
1-800-361-5237
Fax 514-731-0154
sales@abra-electronics.com
- 60 -
TGJ3E (Microelectronics)
Addison Electronics Ltd. (excellent
source for speakers, etc.)
8018, 20e Avenue
Montreal, P.Q. H1Z 3S7
Tel: 514-376-1740
Active Surplus
345 Queen Street W.
Toronto, Ontario
M5V 2A4
1-800-465-KITS
Electrolab Training Systems
Belleville
http://www.elabonline.com
Radio Shack (crossovers)
(see local phone book)
Books, Texts
 Dickason, Vance. The Loudspeaker Design Cookbook. Audio Amateur Press, New Hampshire,
1995. ISBN 1-882580-100-9
 Petruzella, Frank D. Introduction to Electricity and Electronics. McGraw-Hill Ryerson, Toronto,
1986. ISBN 0-07-548899-X (Book 1), ISBN 0-07-548900-7 (Book 2)
Websites
The Speaker Building Page http://www.hi-fi.com/speaker/
Audiomatica SA (manufacturer's of CLIO sound spectrum analyzer) –
http://www.mclink.it/com/audiomatica/clioeng.htm
SpeakerBuilding.comhttp://www.speakerbuilding.com/
Unit 2: Activity 3
- 61 -
TGJ3E (Microelectronics)
Appendix 2.3.1: Project Loudspeaker Design Brief
Title:
Project Loudspeaker
Activity:
Time:
Students design a crossover
network for a three or two way
loudspeaker system
8 -10 hours
Course:
Communications Technology
Grade 11 Workplace
Date:
RATIONALE
Loudspeaker systems are ideal for demonstrating the physics and the concepts of electromagnetism,
signal manipulation, test measurement systems and signal reproduction. Through the design of a
crossover network (a filter circuit), you will have the basic procedures to design and build any
electronic device that requires the transmission and receiving of electronic signals.
THE ASSIGNMENT
You will design and build a crossover network for a two-way or three-way loudspeaker system.
LEARNING EXPECTATIONS: You will:






manipulate electronic signals
calculate inductance and capacitance in order to direct signals to output devices
define and describe the types of audio speakers, enclosure types and physical parameters of
speaker systems
test and analyze communication signals
describe the process of filtering electronic signals
illustrate circuit diagrams and write test reports
TOOLS AND MATERIALS
Crossover circuit diagrams
capacitance meter
coils or chokes
audio amplifier
Unit 2: Activity 3
calculator
inductance meter
resistors
speakers (tweeter,
midrange, and/or
woofer subwoofer)
- 62 -
multimeter
oscilloscope
breadboard
variety of capacitors
fuses
L-Pads
either test speaker enclosures or materials for
fabricating speaker enclosures
TGJ3E (Microelectronics)
EVALUATION
Deliverable
#
(periods)
Mark
weighting (%)
Time
1
Test report
2
20
2
3
4
Completed circuits
Presentation
Vocabulary test/report
TOTALS
4
2
2
10
30
30
20
100
Notes
Math calculations, diagrams,
test results, observations
Clean, precise work
Knowledge of facts
NOTES
ALL CIRCUITS MUST BE INSPECTED BY TEACHER BEFORE POWER IS APPLIED
All reports must be word processed, diagrams or images to be created using illustration or CAD
software.
Each individual in a group or team must hand in their own reports.
WHEN IN DOUBT, ASK!
VOCABULARY
Audio frequency
Frequency response
Amplitude
Power
Decibels
Electromagnet
Coil
Choke
Impedance
capacitor
Capacitance
Inductance
Tweeter
Distortion
Clipping
Hertz (Hz)
Low pass filter
Band pass filter
Notch filter
High pass filter
Cutoff frequency
Octave
Midrange
Woofer
Subwoofer
Enclosure
Crossover network
L-pad
Fuse
PROJECT
STEP STUDENT ACTIVITIES
1
Review the circuit diagrams and collect the necessary parts. Retain all calculations and
notes for the final report.
2
Obtain components, breadboard, etc. and build the circuit required. Obtain permission
from the instructor to apply power to circuit. Test and troubleshoot till you have a working
circuit. SHOW COMPLETE CIRCUIT FOR MARKING
3
Test circuits using speakers to listen for sound quality, and using meters to measure
signal strength Develop the test report and include circuit diagrams, calculations and
results in an engineering test report fashion. Include log sheets. Include vocabulary if
required. HAND IN REPORT FOR MARKING
4
Present your findings to class and instructor.
Unit 2: Activity 3
- 63 -
TGJ3E (Microelectronics)
Appendix 2.3.2: Support Materials for Project Speaker
PROJECT SPEAKER TERMINOLOGY
Sound
Frequency
Hertz
Amplitude
Decibels
pressure waves in fluids, gases or solids
number of peaks per given time period
unit of frequency, cycles per second (Hz)
loudness or intensity of vibrations
-ratio of 2 sound amplitudes, (dB), logarithmic scale
-0dB: barely heard 1000Hz signal by human ear in quiet
environment
-change in 10dB: twice as loud
- 90dB: 109 or billion times louder
Sound
Pressure Level (SPL) amplitude of sound in decibels
Amplification
increasing electrical signal amplitude
Echo (Reverberation) reflection of direct sound waves off of surfaces
PARTS OF ELECTRODYNAMIC SPEAKERS
(see diagram)
driver (coil and magnet)
frame or basket
bobbin
spider
suspension or surround
cone
dust cap
Piezoelectric speakers
Electrostatic speakers
Unit 2: Activity 3
- 64 -
TGJ3E (Microelectronics)
TYPES OF SPEAKERS
Project Speaker
Woofers



low range, bass, 20 to 1000Hz
range from 4" to 16", usually 10" to 12"
made of felted paper, polypropylene
Midrange





broad spectrum, 1000Hz to 10kHz, most efficient 1kHz to 4kHz
best for voices, most instruments
range from 3" to 8"
paper, cloth, poly
some domed for wide dispersion
Tweeter




high or treble range, 4kHz to 20kHz
usually under 2"
paper, plastic, metals
suffer from narrow dispersion, horns, baffles, domes
used to disperse sound
Full Range



adequate for covering full spectrum
typically used in car systems
usually inexpensive
Coaxial/Triaxial

woofers and midranges or midranges and tweeters with
individual coils in common magnets
Whizzer Cones


woofers and midranges with separate cone attached to coil
improves frequency response
Unit 2: Activity 3
- 65 -
TGJ3E (Microelectronics)
SPEAKER DESIGN FACTORS
Project Speaker
Power Rating







amount of power speakers can handle
rating in watts RMS
two ratings:
1) peak (short duration)
2) average (continuos)
if exceeded can overheat coil and cause permanent damage
improve by cooling systems, such as ferrofluid
most power absorbed by woofer (half of power between 75Hz and 500Hz)
typical woofer is 50W to 60W
Magnet Size



lager the magnet, the greater force to react to coil
usually 15 to 20 oz., some to 50 oz.
rare earth magnets best
Cone Material


cloth or paper distorts with age
poly lasts longer, takes more stress
Suspension


folded paper best for ported reflex
rolled polyfoam or butyl rubber more compliant for acoustical suspension
Impedance



resistance to AC signals, in ohms
most systems 8 ohms, some 4 ohms
depends on multiple speaker configuration
Unit 2: Activity 3
- 66 -
TGJ3E (Microelectronics)
SPEAKER DESIGN PARAMETERS
Project Speaker
Frequency Response






range of frequencies an audio system can reproduce accurately
usually a variation of speaker output over the range of frequencies
flat means perfect response across spectrum
if dips in response- sound "colored"
measured in decibels (ratio of output power to input power)
the higher the dB, the greater the output power for any given input power
Sound Dispersion





spreading of sound leaving speaker
the wider the dispersion the better
speakers omnidirectional up to certain frequencies
tweeters worst
Dispersion limit frequencies:
15"
880Hz
4"
3.3kHz
12"
1.1kHz
2:
8kHz
8"
1.65kHz
Damping



cone should follow applied signal
unwanted motion due to unwanted signals should be damped out
speaker components that apply damping:
cone material (stiffness)
suspension (compliance to movement)
spider (made to restrict motion)
magnet (heavier = more shock absorbing)
enclosure (air pressure)
Sound Distortion



unwanted applied electrical and mechanical noise
changes or colours sound by altering or adding frequencies or amplitudes
Types:
Harmonic distortion:
 added frequencies in signal, or imperfect driver behavior at high volumes
Noise:
 damaged components, raspy sound, i.e., torn cone
Transient response:
 time delay in responding to rapid signal changes
Clipping:
 bottoming out of speaker, running out of travel, esp. woofers
Unit 2: Activity 3
- 67 -
TGJ3E (Microelectronics)
CROSSOVER ELECTRONICS
Project Speaker
Wiring the Speaker
The louder it is, the more power, hence the larger (diameter) the wire required to prevent heat
and reduce the voltage drop. Also the longer the distance, the larger the wire required
(voltage drop).
Wire Gauge
AWG 14
AWG 16
AWG 18
Capacity
15A
6A
3A
Speaker Polarity
General Rule: red = positive, black = negative or ground, (RCA plugs…note centre post
polarity)
Impedance
Input and output impedance (frequency dependant resistance) must match, i.e. 8, 4
In series circuits, impedance doubles, in parallel circuits it halves.
L-Pads
 better than fixed resistors to control volume of independent speakers in enclosures.
 L-Pad: variable resistance, constant impedance
Fuses
 used inline on the positive terminal to protect speaker from over-current load
A=
where
P/Z
A = fuse amperage, P = power of speaker in Watts, Z = impedance in ohms
Speaker Enclosures
 too big: boomy sound
 too small: flat bass sound
Unit 2: Activity 3
- 68 -
TGJ3E (Microelectronics)
CROSSOVER NETWORKS
COMPONENTS

role of crossover is to protect tweeter or midrange from low freq. overload

crossover freq.: that freq. where you cut off response down to 3dB

Capacitors:
used to cutoff lows: (high pass filter), uses principle of RC lag
Coils:
cuts off highs, (low pass filter), uses principles of back EMF due to
magnetic field

TYPES OF CROSSOVERS






Note: common midrange crossover: 1500Hz-6000Hz
common tweeter crossover: 6000Hz-20kHz
2 kinds of crossover circuits: series and parallel circuits
crossovers named by number of drivers: 2 way or 3 way, etc.
3 kinds of crossover filters:
low pass
high pass
band pass
simplest: 1st order (cutoff slope 6dB/octave)
 high pass capacitor in series with resistor
 3dB is where impedance of cap = impedance of tweeter
 to move crossover point higher: use smaller capacitor
Common 2 way
Woofer dia.
Freq. (Hz)
8”
2500
10”-12”
1600
Common 3 way
8”
1000/5000
10”-12”
700/4500
15”
600/4500
Unit 2: Activity 3
- 69 -
TGJ3E (Microelectronics)
CALCULATING CAPACITOR (HIGH PASS) VALUE
C = 1/(2 f Xc)
or
C = 15900/(f Rt)
where
Xc = capacitance reactance (reactance = “react against”)
Rt = impedance of tweeter
C = µF
f = frequency i.e. 4000Hz
CALCULATING CHOKE (LOW PASS) VALUE
Coils (also called chokes, inductors)
 used in series with woofer, Inductance (L) measured in Henries or mH
L = 159 Rw/f
where
Unit 2: Activity 3
Rw = impedance of woofer
f = crossover freq.
- 70 -
TGJ3E (Microelectronics)
SPEAKER ENCLOSURE DESIGN
Project Speaker
Enclosures


"bare" speakers do not perform well because back sound waves can cancel some waves
from the front, causing distortion
speakers are placed in "enclosures" to contain back waves, damp out unwanted
frequencies, improve performance and efficiency, and enhance low frequencies
ENCLOSURE TYPES
Acoustic Suspension


air tight enclosure
speaker is cushioned or suspended by air inside enclosure (damping)
Infinite Baffle

very large sealed enclosure, low suspension or damping
Ported Reflex




also called ducted port, bass reflex, Helmholtz resonator)
tubed port in enclosure, open to front
size and length of port is critical for tuning
deeper bass response and higher efficiency
OTHERS




Double Woofer
Double Chamber Reflex
Tapered Pipe
Labyrinth or Transmission Line
Unit 2: Activity 3
- 71 -
TGJ3E (Microelectronics)
DECIBEL SCALE
Project Speaker
Sound Production
Decibel Scale
(dB)
Explosion
Threshold of Pain
Auto Horn at 20 ft.
Heavy Trucks at 20 ft.
Train Whistle at 500 ft.
Vacuum Cleaner at 10 ft.
Average Traffic at 100 ft.
Normal Speech at 3 ft.
Light Traffic at 100 ft.
130
120
110
100
90
80
70
60
50
40
30
20
10
0
Soft Whisper at 5 ft.
Very Soft Whisper at 1 ft.
Threshold of hearing
Unit 2: Activity 3
- 72 -
Notes
Night Club
Loud Music 30 W
Soft Music 0.01 W
TGJ3E (Microelectronics)
PARTS OF
THE ELECTRODYNAMIC SPEAKER
FRAME
SPIDER
CONE
BOBBIN
DUST CAP
SOFT IRON
CORE
WIZZER
CONE
VOICE COIL
SUSPENSION
PERMANENT
MAGNET
Unit 2: Activity 3
- 73 -
TGJ3E (Microelectronics)