Assignment Report FOR INTERNAL USE PP/1979-8Q/1/4.3/10 NOT FOR GENERAL DISTRIBUTION Contribution to the development of infra­structures and training of personnel for technical and vocational education

REPUBLIC OF IRAQ

VOCATIONAL SECONDARY EDUCATION IN ELECTRONICS, RADIO AND TELEVISION

by T. Ortman

United Nations Educational, Scientific and Cultural Organization

Paris, February 1980

This report represents the views of the author and not necessarily those of Unesco or the Government of Iraq

Serial No.: FMR/ED/STE/80/102

Technical Report PP/1979-30/1/4.3/10 FMR/ED/STE/80/102(Ortman) 29 February 1980

Table of Contents

Page

The School System in Iraq 1

INTRODUCTION 3

SECONDARY ELECTRICAL TECHNICAL SCHOOL, BAGHDAD 3

The scholastic year 4

Comments on the present syllabus . . . 4

Staff-student situation 4

Workshop facilities 4

SEMINAR ON TEACHING METHODS FOR ELECTRONICS 5 (23-25 October 1979)

Objectives 5

Programme 6

Outcome of the Seminar 6

Comments 7

RECOMMENDATIONS 7

APPENDICES

1. Proposed syllabus for electronics, radio TV . . . . 9

2. Seminar Papers 13

3. Persons contacted by the consultant 25

The School System in Iraq

P r-- m a ry school (5 y e a r s )

Inte rmedi ate ¡•̂ school

(3 y e a r s )

X

Secondary school 3 years

Academi c

Vocati onal

Centres of Vocational Trai ni ng

Un i ve rs i t;

^

XI

T e c h n i c a l Ins t i tu tes (2 y e a r s )

( M i n i s t ry of I n d u s t r y )

- 3 -

INTRODUCTION

Under the Participation Programme of Unesco 1979-1980, a consultant mission was undertaken to Iraq with the following terms of reference:

(a) to study the present syllabi for the subjects of radio and television theory and practice of the secondary industrial schools, and suggest modifications in order to improve these syllabi based on modern trends and on the needs of Iraq;

(b) to conduct, with the co-operation of the Government, a short training workshop for Iraqi teachers of those subjects mentioned in (a) above.

The consultant was in Iraq from 2 to 30 October 1978.

The consultant was based at the Secondary Electrical School, Baghdad. All information needed to enable the consultant to fulfil his assignment was written in Arabic. Information about the school system, curriculum, syllabus, staff and students was therefore obtained mostly by questioning Iraqi counterparts. The Iraqi counterparts were very co-opeative and hospitable. The consultant found the mission to be a very pleasant experience.

ELECTRONICS (RADIO/TV) SECONDARY ELECTRICAL TECHNICAL SCHOOL

Curriculum

Subjects

Religion

Sport

English

Arabic

Social study

Mathematics

Physics

Chemistry

Technical Drawing

Electronics Theory

Practical Work

Total

Total

Hours weekly 1st, 2nd, and 3rd year

Class Workshop

45 min.

45 min.

1 h. 10 min.

1 h. 10 min.

35 min.

1 h. 45 min.

1 h. 10 min.

1 h. 10 min.

2 h. 10 min.

3 h. 30 min.

14 h. 10 min

18 h.

18 h.

- 4 -

The scholastic year

1 September - 30 September

1 October - 14 January

15 January - 31 January

1 February - 14 February

15 February - 14 May

15 May - 31 May

1 June - 30 June

1 July - 31 July

Comments on the present syllabus

Preparation for teachers

Teaching

Mid-year examination

Holiday

Teaching

Final examination

Preparation for teachers

Holidav

The total time for the course in electronics is about 2,000 hours. The training is divided into two parts:

electronics theory - 315 hours (15%)

practical work - 1,720 hours (85%)

The theory has a very small percentage of the course. 30-40% theory and 60-70% practical work would be more suitable.

There is a need to improve the co-ordination between theoretical and practical teaching.

The present syllabi deal far too much with electron tubes at the expense of modern electronic technology.

The first two years of the course could be given a more general approach to electronics in order to enable training in other applications of electronics, radio and TV to be dealt with in the 3rd year as a specialization.

Example :

Basic

Electronics

(2 years)

Industrial Electronics

•Telecommunication

Radio and TV (Home electronics)

(1 year)

Staff-student situation

About 300 students in electronics (Radio/TV) graduate each year from secondary technical schools in Iraq.

- 5 -

The Secondary Electrical Technical School in Baghdad has approximately 1,000 students and 50 teachers. In the electronics department there are 5 teachers, teaching electronics theory, 11 teachers teaching practical work, and around 460 students. The teachers in theory have a fair theoretical background, a degree in engineering, and many of them have had the opportunity of overseas training.

The practical teachers generally have a very poor training in their profession; many are secondary school-leavers without any practical experience. The consultant did not meet one teacher in practical electronics who had formal training in teaching. Very little co-operation between the practical and theoretical teachers was shown. The practical teachers use 85% of their time for training in electronics.

Workshop facilities

At present, there are 5 secondary technical schools in Iraq with departments for electronics.

The Secondary Electrical Technical School in Baghdad was built in 1969. The consultant was told that this school is one of the best technical schools in Iraq for electrical/electronics training.

The electronics department of the school has 6 workshops, each designed for about 16 students, and one laboratory. The workshops and classrooms for theory are separated into different buildings. Due to bad workshop management, workshops and equipment are in bad condition.

There are some difficulties in purchasing electronics components. With assistance from the Foundation, it is possible to import what is needed. Some sophisticated equipment, trainers and instruments have been purchased and put into the laboratory.

There are 28 new technical schools under construction in Iraq. The schools are being built by a Finish company. The consultant had the opportunity to visit one of the new schools which was nearly completed and very impressive. This school was designed for 650 students.

SEMINAR ON TEACHING METHODS FOR ELECTRONICS (23-25 OCTOBER 1979)

The consultant arranged the laboratory at the school for the Seminar. Work­benches were put in, electricity supplied to the benches and instruments, which had never been used, were unpacked and put into working order.

A programme of 7 exercises (Appendix 2) was worked out. Existing equipment was used and 3 connection-boards were designed. A connection diagram was pasted on a sheet of wood, tacks knocked in and the circuits connected.

Objectives

To introduce teaching methods in electronics; to teach the use of semi­conductors, transistors, UFT, SCR; to exercise the use of electronic instruments.

The Seminar was designed mainly to deal with modern techniques in electronics, new components, etc., which are likely to be included in a revised syllabus.

- 6 -

The approach to electronics practice consists at present of learning by rote. Due to lack of workshop management, equipment and the few instruments available were in very poor condition.

The practical teachers have received poor training. Most of them are secondary school-leavers without any practical experience. On the last day of the mission, the consultant was told that there exists a two-year course at the University for technical teachers, and that some of the staff at the school had completed this course. The consultant, however, could see no difference in the competence of these teachers.

The consultant drew the conclusion that it would be most beneficial for the staff if the Seminar were to contain an integration of electronics theory, teaching methods and workshop management. It was agreed that the Seminar should be of 3 days' duration. A programme for the Seminar was worked out with the intention of it being run in a similar way to how the practical work in electronics should be conducted in the workshops. Twenty-four teachers from different schools attended the Seminar.

Programme

1st Day

A. Teaching methods

(i) The objectives for practical work in electronics to prove the theory; to learn manual skill; to develop good working habits.

(ii) Types of practical work. Exercises in measurements integrated with practical explanations of the theory (examples of this type of work were demonstrated in the Seminar by exercises) , Learning manual skills e.g. soft soldering, connections, etc.

(iii) Project work. Manual skills integrated with theoretical knowledge and techniques of measurement. Example: Building and testing of amplifiers, rectifiers, oscillators, etc.

(iv) Work with the ready product. Testing, tuning, trouble-shooting on radio/TV, etc.

B. Workshop management

Arrangement to tools, instruments, work-benches, etc.

2nd Day

Practical work

3rd Day

Practical work Evaluation

Outcome of the Seminar

The first day of the Seminar proceeded according to plan. The teachers exposed a weakness in electronics.

- 7 -

The second day, dealing with practical work, did not proceed as planned. The teachers had great difficulties in working from written instructions and in operating the instruments. Also, lack of theoretical knowledge, electronics and basic calculations created difficulties. For these reasons, the teachers were able to complete only one out of seven exercises.

The consultant changed the programme for the third day which was then used to train teachers in measuring frequencies and voltage with the oscilloscope.

The manager of the school and one representative from the Foundation were observers at the Seminar. They expressed great surprise that the standards of the teachers were as low as shown in the Seminar.

It should, however, be pointed out that the teachers showed great interest in the Seminar and some of the topics brought up were applied in the workshops several days later.

Comments

Unfortunately, 3 days was too short a time. A great interest for the Seminar was shown, however, and the consultant got the feeling that it was appreciated.

Appendix 2 refers to the papers prepared for the Seminar.

Recommendation s

1. In order to improve the training in electronics (Radio/TV), there is a need to revise the syllabus. The consultant has written a syllabus for a 3-year course in electronics (Radio/TV)(Appendix 1), which could serve as a guide for the revised syllabus. The consultant would like to point out that he had a very short time at his disposal for this consultancy and that the proposed syllabus therefore only deals with the main topics.

2. In order to be able to fulfil the intentions of the revised syllabus there is an urgent need to upgrade the teachers in practical work in modern electronics technology, in workshop management and in teaching methods. An initial one-year full-time course should be considered.

3. A secondary electrical technical school should be developed into a training centre for teachers in electronics and power electricity. The objectives for this training centre should be:

(a) To run in-service courses for teachers in the field.

(b) To train new teachers.

(c) To produce teaching aids (job instruction sheets, etc.).

(d) To give advice about suitable material for eaching (instrucments, trainers, etc.).

4. There is an urgent need to develop and use teaching aids to a greater extent in the teaching process.

5. A programme of in-service teacher training must be considered to upgrade the level of the existing staff, especially in teaching methods and the use of equipment for practical work.

- 8 -

6. The consultant wishes to recommend that the Iraqi Government seek Unesco's advice and assistance in preparing the technical teachers and instructors for the new schools under construction, and for the management of these new schools.

- 9 -

APPENDIX 1

Proposed syllabus for electronics, radio/TV Secondary Technical School

1st year

Topic

1. Electrical safety

2. Basic electrical installation

3. Soft soldering

4. Direct current DC

m

Techniques of measurement (1)

Theory

Electrical distribution

Why earthing? How electric current effects the human body

Wiring rules

Fuses Cables Plugs Outlets Basic installation

Solder Tools etc.

How electricity is produced

Volt Ampere Watt Electric circuit etc.

Voltmètres Ammetres Ohm metres Multimètres Oscilloscope Audio frequency Generators RLC bridges

Practical

Connection of plugs, outlets, lampholders, simple installation

Soldering on: net terminals printed circuits etc.

Measurement of current voltage power etc.

Exercises in the use of the listed instruments. To be integrated in other exercises.

Time T P

- 10 -

1st year t

1 Topic i

6. Alternating current

7. Mechanical work

8. Electronics (1)

9. Alternating current

10. Electronics

Theory

AC generation The sine vave Frequency Time Resistive AC circuit The transformer

Passive components: resistors capacitors terminals and contacts used in electronics wires and cables switches semiconductor diodes

Relays

Reactance Power factor Power in AC circuits RC circuits RL RLC LC Resonance

Transistors: germanium silicon

CE connection CB CC Special components: photo devices zener diode tunnel diode field effect transistor MOS transistors

Practical

Measurement with oscilloscope and meters : Time frequency U and RMS value PP

To determine the' characteristic for germanium diodes silicon diodes zener diodes The connection of simple rectifier circuits.

Time T P

2nd year •

- 11

2nd year

Topic

10.. Electronics

(cont.)

11. Techniques of measurement (2)

Theory

UJT transistors SCR Electrone tubes Integrated circuits IC, LSI

Rectifier circuits Stabilization Current limit Over load protect. Audio frequency

amplifiers Decibel Feedback Harmonic distortion Frequency range Operational amplifiers

Hf amplifiers: wide band amplifier selective amplifier band with Q factor

Modulation AM, FM Oscillators IF amplifiers Mixers Detectors AM, FM Power amplifiers Digital technique:

analog - digital pulses binary system logical functions AND, OR, NOR, etc. relaxation oscillator sequency circuit

Record player Tape recorder Superheterodyne receiver

Oscilloscope MF generators Frequency counters

Practical Time T P

12

Topic Theory

3rd year

Practical Time

12. Electronics

Antennas and transmission lines

Tape recorders FM receivers Tuning and measurement

on the discriminator curve etc..

Stereo amplifiers Stereo radio

TV, black and white

Colour TV, Basic.

- 13 -

APPENDIX 2

Internal resist,

of a battery

Transistor in

CE connection

Transistor in

CB connection

Transistor in

CC connection

Stab, circuits

using semicond.

Voltage régulât.

ÜJT and SCR

Prep, for demonstr.

Tuned circuits

Project work

•

SEMINAR PAPERS

RECORD FOR PRACTICAL WORK

Name:

- 14 -

Secondary Electrical Technical School

Baghdad Iraa

Information sheet The Internal Resistance of an Electrical Power Source

name

class

Every source of electric power can be represented by an Electromotive Force (E) which is constant, and an Internal Resistance (Ri) connected in series.

If the power source is unloaded, no current will flow, there will be no voltage drop across Ri, and the terminal voltage (U) will be the same as E.

If the power supply is loaded with a resistor (Rl), a current (I) will flow, and there will be a voltage drop across Ri (Uri)

I = Ri Rl

6^?

U

h Ú "i: _ 1 ~

With reference to equation A what will happen to the current I if Rl is decreased?

Answer:

The voltage drop across the inernal resistance (Ri) will be:

Uri = Ri B Ri + Rl

With reference to equation B, what will happen to Uri if Rl is decreased?

Answer :

If Kirchoff's Law is applied to the circuit

E - Uri - Uri = 0 C

With reference to equation C, what will happen to the terminal voltage Uri if Uri is increased?

Answer:

Exercise The terminal voltage of a battery was measured to 6V when the battery was un­loaded. When the battery was loaded with a resistor of 2 ohm, the terminal voltage dropped to 4V. Calculate the internal resistance of the battery.

- 15 -

Secondary Electrical Technical School

Baghdad Iraq

Worksheet Measurement of the Internal Resistance of a Battery.

name

class

Objectives: To get a practical application on Ohm's Laws. To exercise the handling of the oscilloscope and the RLC bridge.

Material: 1. Oscilloscope with probe set

RLC bridge

Multimeter

Battery

Resistor

Procedure: 1. Measure the resistance of the load resistor with the RLC bridge.

Record the result: R =

Measure the terminal voltage of the battery when it is unloaded. Use the multimeter.

Record the result: U =

Repeat the measurement (2) but use the oscilloscope this time.

Record the result: U =

Connect the resistor across the battery terminals and measure the terminal voltage when the battery is loaded. Use the multimeter;

Record the result:

Conclusion: Now, all information needed to calculate the internal resistance is available.

Calculations:

Answer :

Remarks: In this exercise the power source was a battery. The same method can be used to determine the output or input impedance of an amplifier.

- 16 -

Secondary Electrical Technical School

Baghdad Iraq

Work sheet The transistor in GE connection

name

class

Theory: The GE connection has a rather high current and voltage gain. Consequently the power gain is high too.

The input impedance is around Ik in parallel with Rl.

The output impedance is around 10 k. in parallel with RC.

In this exercise you are going to measure the input and output impedance, the voltage - and current gain and adjust the bias to its correct value.

Material: 1. Connection board with transistor AC 122.

1. DC power supply (9V)

1. Audio frequency generator.

1. Double beam oscilloscope.

1. Multimètre

1. Decade resistor

Diagram:

£

\i—L

£c

• O f

Procedure : A. Biasing

1. Connect the power supply to 3 and 5 (positive to 5) Adjust to 9V.

2. Connect a voltmètre between 5 - 6 .

3. With the variable resistor, adjust the voltage between 5 - 6 to 4,5V.

Measure UBE and UCE, record.

UCE = , UBE =

Calculate IC:

IC

Mark the biasing point in the collector diagram Draw the load line.

- 17 -

The transistor in CE connection (Cont.)

B. The voltage gain

1. Adjust the frequency generator to 1,000 Hz and the output voltage to zero.

Connect to 1 - 2 (screen to 2)

2. Put the input selector switches of the oscilloscope in AC position.

3. Connect CHI input of the oscilloscope to 1 - 2 and the CH2 input to 4 - 5 (screen to 5)

4. Increase the output voltage from the generator until both peaks are distorted at the output of the amplifier.

5. Decrease the output voltage from the generator about 50%.

6. Measure the input and output voltage of the amplifier and record.

Uin + = PP

Uout PP

Calculate the voltage gain.

Answer:

C. The input impedance

1. Keep the same connection as used in R and connect a decade resistor in series with the generator.

2. Put the decade resistor to zero and read the output voltage from the amplifier.

Uout = PP

3. Adjust the decade resistor till Uout is half the value recorded in 2.

4. Read the resistance value of the decade resistor. This is the same as the input impedance of the amplifier.

Zin

What should happen to the input resistance if Rl was increased?

Answer :

Exercise;

Apply the same method as used in C and measure the output impedance of the amplifier. Draw the circuit diagram.

Zout =

- 18

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- 19 -

Secondary Electrical Technical School

Baghdad Iraq

Work sheet The Transistor in CB connection

name

class

Theory:

Material:

Connection diagram:

In CB connection the base is the common electrode for the input and output.

A transistor in CB connection can be used at higher frequency than if connected in CE. For that reason the CB connection is often used in radio and TV receivers.

The CB connection has high voltage gain, but no current gain.

The input impedance is low, the output impedance is high.

Connection board with transistor AC 122 in CB connection.

DC power supply (9V)

Audio frequency generator.

Double beam oscilloscope

Decade resistor or a variable resistor

Multimètre.

. a.

-c -

(Mf «JT

x

-a

-0 +

Procedure: A.

1.

2.

Biasing

Adjust the power supply voltage to 9V.

With the variable resistor, adjust UCE to 4V.

Measure and record the following voltage

UE = , ÜBE =

Calculate the collector current

UCE

- 20 -

The transistor in CB connection (cont.)

B. The voltage gain

1. Adjust the frequency generator to L 1,000 Hz and the output voltage to zero.

Connect to the input of the amplifier (1 2)

3.

Connect the CHI input of the oscilloscope to measure the input voltage to the amplifier, and CH2 to measure the output voltage.

Increase the output voltage from the generator until both peaks of the output signal is distorted, then decrease the input signal about 50%.

Measure and record:

Uin = PP

Uout PP

Calculate the voltage gain.

Voltage gain =

What, is the phase difference between the input and output signal?

Answer :

C. The input impedance

1. Connect as shown in diagram.

2. Put the decade resistor to zero ohm.

3. Read the output voltage from the amplifier at the oscilloscope.

Connect

Uout pp

Increase the resistance of the decade resistor until the output voltage from the amplifier is half the value recorded in 2. The input resistance of the amplifier equals the resistance value of the decade resistor.

Zin =

- 21 -

The transistor in CB connection (cont.)

D. The output impedance !

1. Connection: ( ̂

2. Measure the output impedance, use the same method as used when the input impedance was measured.

Zout =

E. The current gain

Calculate the imput current:

Calculate the output current:

Calculate the current gain:

Lin =

lout =

Current gain =

O '+•

F. Determine the frequency range for the CB amplifier.

0 ¿IB , _ _

-^¿6.-

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l<? O ICCO ißK lùOk IffOOk -5»

»CK iOOK. Hz

Voltage gain = dB = 20 log

Power gain dB = lo 10 log

Uout Uin

Pout Pin

- 22 -

Secondary Electrical Technical School

Baghdad Iraq

Work sheet The transistor in CC connection.

name

date

Theory:

Circuit diagram

Procedure :

The CC connection is called the emitter follower.

The emitter is the common electrode for the input and output signals.

The CC connection has a high current gain but no voltage gain.

The input impedance is high and the output impedance is low.

The CC connection is often used as an impedance transformer.

Z OL.

s-'l W"

I ^J? + In the theory it was stated that the collector is the common electrode for the input and output signals.

With reference to the diagram, explain that statement.

The imput is between 1 - 2 , and the output is between 7 - 8 .

Answer :

A. Biasing

Set the biasing to its correct value

Calculate IC.

C. Voltage gain

Determine the voltage gain,

'5-8

IC =

U gam =

D. Input and output impedance Measure the input and output impedance:

Z. in out

E. Calculate the current gain.

in out •r I

gaxn

- 23 -

Secondary Electrical Technical School

Baghdad Iraq

Worksheet Voltage regulation with UJT and SCR

name

class

Material: 1. Electronic Trainer VÉNETA with instruction book

I. Oscilloscope with probe set.

1. Frequency Counter, TAKEDA, TR-5142G with manual.

Procedure: Read the Instruction Manual for the Frequency counter, Chapter 2 specifications, chapter 3 Operating instructions.

Head the instruction book (Electronic VÉNETA) Page 163-164

Copy and study the circuit diagram. Circuit diagram:

Connect up the circuit on the board, assembling diagram page 166.

Contact the teacher for check up.

Test the function,

Put the variable resistor in the centre position, measure and copy the following curves, (use the oscilloscope) Measure the frequency with the frequency counter.

lie A

-^

*¿' A

-?-

U IS U 2. O

- 24 -

Secondary Electrical Technical School

Baghdad Iracr

Stabilizing circuits using semiconductors

name

class

Material: Electronic trainer, ELWE - FRANZ System with experiment book

Procedure: 1, Read in the experiment book, page 6-70.2 to 6-70.4.

2. Copy the circuit diagram and study the function. Circuit diagram:

Questions:

3. Connect and test the function.

1. What should happen to U„ if the zener diode was burnt and the contact between the anode and the cathode was interrupted?

Answer:

2. What should happen to (J if transistor T was short-circuited?

Answer :

3. What should happen to U_ if transistor T was short-circuited?

Answer :

- 25 -

APPENDIX 3

PERSONS CONTACTED BY THE CONSULTANT

Mr. Kaled Abdu Sallam Assistan Director, Foundation for Vocational Education

Mr. M.H. Al-Naib (Mr. Motheer)

The Manager of the Secondary Electric Technical School

Mr. S. Ibrahim (Mr. Saad)

Assistant Manager of Technical Affairs

Mr. R. Alansair (Mr. Rother)

Head of Electronics Department (Textbook author)

Mr. H. Al-Khattar Part-time teacher at the School and Director of the Institute of Electronics (Textbook author)

Mr. Clewestam Project Co-ordinator IRO/L 846 - Unesco/IBRD Education Project