The document outlines a professional course in mobile phone repair offered by the Dar es Salaam Institute of Technology, detailing essential topics such as basic electronics components, their functions, and maintenance techniques. It also includes practical skills like testing components and using various tools, including soldering irons and multimeters, necessary for repairs. Furthermore, it explains fundamental concepts of electricity and essential components needed in electronics, alongside their respective functions.

1. DAR ES SALAAM INSTITUTE OF
TECHNOLOGY
PROFFESSIONAL COURSE FOR
MOBILE PHONE REPAIR

2. IDENTIFY ELECTRONIC COMPONENTS, FUNCTIONS AND
THEIR MAINTENANCES
(a)Electricity basics
(b)List basic electronic components
(c)Draw symbols for basic electronic components
(d)Explain the function (s) of resistors, Capacitor, Diode, Transistor, Inductor and
Integrated Circuit (IC)
(e)Test electronic components ( identify faulty and working components)
(f)List electronic maintenance tools
(g)Explain the function of cutter, strippers, pliers, soldering iron (gun), soldering wire,
metre, screw driver, tweezers, knife, driller, blower, benzene, brush, lens , pin, etc.
(h)Perform : cutting, stripping, soldering, measurement, screwing/unscrewing,
blowing, cleaning, etc
(i) Test electronic components ( identify faulty and working components)

3. • Electricity basics
Electricity is the set of physical phenomena associated with the
presence and motion of electric charge.
Electronics deals with electrical circuits that involve active electrical
components such as vacuum tubes, transistors, diodes and integrated
circuits, and associated passive interconnection technologies.

4. The flow of electron (Electric current)

5. Electric Potential
 A voltage is the difference in potential between two points in an
electric field. Voltage gives us an idea of just how much pushing force
an electric field has.
A closed circuit of conductive material provides a path for electrons
to continuously flow.
Batteries have two terminals, which connect to the rest of the circuit.
On one terminal there are an excess of negative charges, while all of
the positive charges coalesce on the other. This is an electric potential
difference just waiting to act!

6. Battery charges flow though the circuit

7. Closed circuit

8. • The list of the basic electronics components
Resistor

9.  Capacitor

10.  Diode

11.  Transistor

12.  Inductor

13.  Loud speaker, Buzzer and Microphone

14.  Transformer

15.  Antenna

16.  Crystal Oscillator

17.  Fuse

18. • Symbols of Electronics Components
Electrical Wire
Switch
Earth/ Ground

19. • Symbols of Electronics Components
Resistor Capacitor

20. • Symbols of Electronics Components
Inductor Power supply

21. • Symbols of Electronics Components
Diode
Transistor

22. • Symbols of Electronics Components

23. • Function of different Electronics component
Resistor
The function of resistors are used to
reduce current flow, adjust signal
levels, to divide voltages
and bias active elements.
Capacitor
Capacitor is used to store charges.
It is used for blocking direct
current while allowing alternating
current to pass, it smooth the output
of power supplies, they tune radios to
particular frequencies.

24. • Function of different Electronics component
Diode allow an electric current to
pass in one direction (called the
diode's forward direction), while
blocking it in the opposite direction
(the reverse direction).
diodes are used to regulate voltage
(Zener diodes), to electronically
tune radio and TV receivers
(varactor diodes), to generate radio-
frequency oscillations (tunnel
diodes, Gunn diodes, IMPATT
diodes), and to produce light (light-
emitting diodes).

25. • Function of different Electronics component
Transistor
Transistor is used to amplify and
switch electronic signals and electrical
power.
Inductor
Inductors are used to block AC while
allowing DC to pass(chokes), electronic
filters to separate signals of
different frequencies, and in
combination with capacitors to
make tuned circuits, used to tune
radio and TV receivers.

26. • Function of different Electronics component
Loudspeaker
produce sound from an electrical
signal.
Loudspeaker

27. • Function of different Electronics component
Transfomer
Transformer is used to step up a
current or a voltage and viseversa.
Antenna
Antenna is a transducer which
convert electromagnetic wave to
electrical signal and viseversa.

28. • Function of different Electronics component
Crystal Oscillator

29. • Identfying and Testing Electronics
Components
 Resistors
The electrical function of resistor is specified by its resistance which can be determined from
the color strips bands around the resistor.

30. • Identfying and Testing Electronics
Components
Another parameter to identfy resistor is the Power Rating.
The resistor power rating will determine the power dissipation of that
resistor.

31. • Identfying and Testing Electronics
Components
Capacitor
Electrolytic capacitor
Electrolytic capacitor is identfied from its capacitance, which is directly
labelled on the capacitor body.
the voltage of the capacitor is also obtained
from the capacitor body and the capacitor
must not be connected to the circuit with
voltage above the rated value of the capacitor.

32. • Identfying and Testing Electronics
Components
Ceramic capacitor
Electrolytic capacitors are typically used in power supply applications
for voltage filtering and Ceramic capacitors are often used for radio
frequency and in some audio applications.

33. • Identfying and Testing Electronics
Components

34. • Identfying and Testing Electronics
Components
Electrolytic capacitors are typically used in power supply applications
for voltage filtering and Ceramic capacitors are often used for radio
frequency and in some audio applications.

35. Mobile Phone Repairing Tools & Equipment | Tools to Repair Mobile Cell Phone
Soldering Iron:
Used to solder small components like capacitor, resistor, diode, transistor, regulator, speaker,
microphone, display etc.
.

36. Soldering Station: A soldering station has 2 units – a station and an iron. It has option to control temperature
depending on the heat requirement of the soldering job being done. The soldering iron is attached with the soldering
station. It is better and more convenient than traditional soldering iron.
PCB Holder / PCB Stand: A PCB (Printed Circuit Board) holder or stand is used to old the PCB of a mobile phone while soldering
or repairing. It holds the PCB very strongly and doesn’t allows it to move thus helping in repairing.

37. Solder Wire: Solder wire is used to solder electronic components, Ics, or jumper
Thinner or PCB Cleaner: Thinner or PCB cleaner is used to clean the PCB of a
mobile phone. The most common PCB cleaner used in mobile phone repairing is
IPA or Isopropyl Alcohol
Jumper Wire: This is a thin laminated or coated copper wire used to jumper
from one point to another on the track of a mobile phone while repairing
Blade Cutter: This is used to remove lamination from jumper wire
Point Cutter: It is used for cutting

38. Nose Cutter: It is used for cutting.
Precision Screwdriver: It is used to remove and tighten screws
while assembling and dissembling a mobile phone Precision
screwdrivers of sizes T4, T5, T6 and forehead are good for most
mobile repairing job
Tweezers: These are needed to hold electronic components, ICs, jumper wire etc while
soldering and Desoldering.
Brush: These are used for cleaning the PCB of a mobile phone while
repairing

39. Multimeter: Used to find faults, check track and components
Magnifying Lamp: It is used to see the magnified view of the PCB of a mobile phone
Mobile Opener: These are used to open the housing or body of a mobile phone

40. DC Power Supply: Regulated DC (Direct Current) power supply is used to supply DC
current to a mobile phone. Most repair person used DC power supply to switch ON a
mobile phone without battery