Subject: Computer Hardware and GSM Repairs 1 | Level: Senior Secondary (WASSCE)
This module focuses heavily on identifying what makes up a mobile phone, analyzing its internal block structure and both hardware and software elements.
Key Topics:
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What does PCB stand for in the context of mobile phone hardware?
Printed Circuit Board
The PCB is the foundational board where all other hardware components are mounted and interconnected.
On a mobile phone's Printed Circuit Board (PCB), what is the primary purpose of the copper tracks or traces?
To conduct electrical signals and power between different components.
Traces are etched onto the PCB to act as wiring, electrically connecting components like resistors, ICs, and the battery.
Modern mobile phone PCBs use a multilayer architecture. Which of the following best describes why a multilayer PCB is essential in GSM repair contexts?
It provides independent layers for signal routing, ground, and power, enabling compact designs.
Due to the complex block diagram (Power, Memory, RF, Audio units), multilayer PCBs are required to fit intricate routing in a tiny form factor.
Which basic hardware component is primarily designed to oppose the flow of electrical current in a mobile phone's circuit?
Resistor
A resistor's main function is to restrict or oppose the flow of electrical current, helping to manage voltage levels across the board.
If a Surface Mount Device (SMD) resistor on a PCB is marked '223', what is its expected resistance value? Note: Resistance R relies on a multiplier based on the last digit (10x).
22,000 ohms
A '223' SMD code means 22 followed by 3 zeros (22×103), which equals 22,000 ohms or 22k ohms.
In a mobile phone's power management circuit, transistors are frequently utilized. Which of the following is a primary function of a transistor in this specific context?
To act as an electronic switch to route power from the battery to various ICs.
Transistors in mobile phones primarily function as high-speed switches or amplifiers, essential for routing power within the Power unit.
Which component allows electrical current to flow easily in only one direction, providing protection against reverse polarity?
Diode
A diode functions as a one-way valve for electrical current, commonly used to protect circuits from improper battery insertion (reverse polarity).
Which specialized type of diode is heavily used in a mobile phone's charging section to regulate voltage and protect components from voltage spikes?
Zener Diode
Zener diodes are unique because they permit current to flow in the reverse direction when a specific voltage is reached, making them perfect for voltage regulation.
Integrated Circuits (ICs) in modern mobile phones are predominantly surface-mounted. What does the acronym BGA stand for regarding IC packaging?
Ball Grid Array
Most major ICs like the CPU and Memory use Ball Grid Array (BGA) packaging to save space on the PCB.
Which electronic component stores an electrical charge temporarily and is widely used for filtering in a mobile phone's circuitry?
Capacitor
Capacitors store electrical energy in an electric field and are crucial for smoothing out power supply fluctuations (filtering).
