IT Fundamentals

Computer

is an electronic device that: • Accepts input • Processes data • Stores information • Produces output

IPOS model

• Input → keyboard, touchscreen, mouse • Processing → CPU, memory • Output→ monitor, speakers, printer • Storage → hard drives, SSDs, cloud

Types of Computers

• Desktop PCs • Laptops • Tablets • Smartphones • Chromebooks

Static Electricity

• A buildup of electrical charge on the surface of an object • Happens when two materials rub together (clothes, carpet, plastic, etc.) • Can discharge suddenly when touched, Electrostatic Discharge (ESD) • Even a tiny invisible spark can destroy computer components

Catastrophic

(device stops working immediately)

Latent

(device works for a while, then fails later)

Common Causes of Static

• Walking on carpet • Dry air / low humidity • Rubbing clothes or sweaters • Plastic packaging • Synthetic materials (chairs, clothing

How to Prevent ESD

• Use an anti-static wrist strap • Work on an anti-static mat • Ground yourself before touching components • Keep humidity between 40–60% • Handle components by the edges • Avoid carpeted rooms when working on computers

Static Electricity Myths

“I didn’t feel a shock, so it’s fine.” → Wrong, components can be damaged at levels below human detection • “Only high voltage hurts components.” → Even a tiny charge can fry RAM, CPUs, or motherboard

Bit (b)

smallest unit of data (0 or 1)

Byte (B)

8 bits

Kilobyte (KB)

1,000 bytes (1024 to be exact)

Megabyte (MB)

1 million bytes

Gigabyte (GB)

1 billion bytes

Terabyte (TB)

1 trillion bytes

Speed

How Fast Data Moves

What do bits measure

File size • Storage capacity • How much data fits on a drive

Kbps

thousand bits per second

Mbps

million bits per second

Gbps

billion bits per second

Bits (b) are for

= speed

Bytes (B) are for

= file size / storage

CPU Speed

GHz (gigahertz) • Billions of cycles per second • Higher GHz = faster processing

RAM Speed

MHz / GHz • Transfer rate (DDR4 2400 MHz, DDR5 5200 MHz)

Storage Speed

MB/s (read/write) • HDD: 80–160 MB/s • SATA SSD: 300–550 MB/s • NVMeSSD: 1,500–7,000+ MB/s

Which part is the CPU

The Brain • Executes instructions and calculations • Measured in GHz(speed) • CPUs get hot → need cooling (fans, heat sinks

Which part is the RAM

Short-Term Memory • Holds data and programs currently in use • Much faster than storage • Volatile: it clears when power is off • RAM allows smooth multitasking • 4GB = very basic • 8GB = minimum modern • 16GB+ = recommended

Which part is the Storage

Long-Term Memory • HDD (Hard Disk Drive) • Old technology, mechanical • Slower • Larger capacity, cheaper • Susceptible to physical damage • Makes spinning/clicking sounds • SSD (Solid State Drive) • No moving parts • Extremely fast • Uses flash storage • Makes old computers feel new • More expensive • GB vs TB • 1 TB = 1,000 G

HDD (Hard Disk Drive)

• Old technology, mechanical • Slower • Larger capacity, cheaper • Susceptible to physical damage • Makes spinning/clicking sounds

SSD (Solid State Drive)

• No moving parts • Extremely fast • Uses flash storage • Makes old computers feel new • More expensive • GB vs TB • 1 TB = 1,000 GB

Motherboard

The central circuit board • All components connect here • Has: • CPU socket • RAM slots • Storage connectors • Expansion slots • USB ports • Power connectors

Motherboard

The central circuit board • All components connect here • Has: • CPU socket • RAM slots • Storage connectors • Expansion slots • USB ports • Power connectors

Power Supply

Converts AC → DC • Different wattage ratings (300W…1000W+) • Supplies power to: • Motherboard • CPU • GPU • Drives • Fans

Cooling Systems

• Fans • Heat sinks • Liquid cooling • Thermal paste

System Software

Operating system itself • Device drivers • System utilities

Application Software

Productivity apps: Word, Excel, Google Docs • Media apps: VLC, Spotify • Tools: calculators, browsers, utilities

Install methods:

.exe / .msi (Windows) • App Store / Google Play • Packages (Linux)

Maintenance

• Dust removal (front → inside → back) • Use compress air or electronics vacuum • Checking fans • Cable management

Technician Toolkit

• Everything you need to diagnose, repair, and maintain computers. • Phillips & flat-head screwdrivers • Torxdrivers (T4–T10) • Precision screwdriver kit • Anti-static tweezers • Small needle-nose pliers • Anti-static wrist strap

Hardware/device replacement

Battery • Keyboard/keys • Random-access memory (RAM) • HDD/SSD replacement • Wireless cards

battery symptoms of failure

overheating, rapid drain, swelling, shutdowns

Steps for working on batteries

• Check battery health settings (iOS/Android) • Use manufacturer-approved replacements only • Never puncture or apply pressure to swollen batteries • Follow ESD + fire safety procedures during removal

Common issues with keys

unresponsive keys, stuck keys, liquid damage

Things to remember while releasing keys

Replace top case or keyboard assembly depending on model

to avoid ribbon-cable damage

Use proper pry tools

Symptoms of slow RAM

slow performance, app crashes, random reboots

(many modern devices have soldered RAM)

So you should confirm upgradability.

Steps for replacing RAM

power down → remove back cover → disconnect battery → replace module

Match RAM

type, speed, and form factor

HDD and SDD symptoms

slow boot, clicking, missing OS, storage errors

HDD and SDD replacement

Backup data before replacement • Replace drive → reinstall OS → verify in BIOS/OS

Remember for HDD and SDD

Use correct form factor (M.2 SATA, M.2 NVMe, 2.5")

Wireless cards symptoms

no Wi-Fi, intermittent connection, Bluetooth failures

Steps for replacing a wireless card

Disconnect antenna leads gently (fragile snap-on connectors) • Replace card → reconnect antennas → secure with screws

Biometrics

Types: fingerprint readers, Face ID/IR cameras • Check calibration and driver/firmware issues • Replace sensor modules carefully, often paired to motherboard • Reconfigure biometrics after replacement

Near-Field Scanner Features (NFC)

Functions: tap-to-pay, tap-to-pair • Symptoms: failed payments, no tag detection • NFC antenna often built into back cover or coil assembly • Replace back cover or antenna module if damaged

Wi-Fi antenna connector

weak signal, dropping connection

Steps to fix Wi-Fi antenna

Inspect antenna leads for breaks or improper routing • Reroute cables along original channels • Ensure connectors snap firmly to wireless card • Replace damaged antennas in screen assembly or chassis

Webcam symptoms

black screen, blurry image, no detection

Fix webcam steps

Test in multiple apps first • Replace front/back camera modules as complete units • Avoid touching sensor surfaces • Reseat flex cables before replacing

Microphone symptoms

muffled audio, no input, distorted sound

Fix microphone steps

Test with voice recorder apps • Check for blocked ports, dust, and debris • Replace module or flex cable assembly

Connection methods

Universal Serial Bus (USB) • C/microUSB/miniUSB • Lightning • Serial interfaces • Near-field communication (NFC) • Bluetooth • Hotspot

Near-field communication (NFC)

Use for payments mostly • Only 4cm

Bluetooth

Device must be paired to the phone • Supports, many devices including: • Headsets, mouses, keyboards

Hotspot

Allows internet sharing from a mobile smartphone to laptop

Accessories

Touch pens • Trackpad • Headsets • Speakers • Webcam

Port replicator

Reproduces the functions of the ports on

Docking station

similar to a port replicator but offers more functionality. Docking stations also replicate ports but can contain things like full-sized drive bays, expansion bus slots, optical drives, memory card slots, and ports that are not otherwise available on a laptop

2G

digital technology and were able to handle phone calls, text messaging (SMS) and sending out limited amounts of data

GSM

Global System for Mobile Communications • Used by AT&T and T-Mobile

CDMA

Code-division multiple access (CDMA) • Used by Sprint and Verizon • Uses a PRL (Preferred Roaming List) • It indicates which radio bands, sub bands, and service provider IDs will be searched for, then allows the phone to connect to the correct tower

GSM and CDMA

were not compatible with each other.

3G

allows additional features such as mobile Internet access, video calls and mobile TV

4G

WiMAX and Long-Term Evolution (LTE) where 2 stardards, LTE won. • Faster than 3G, Theoretical max is 300Mbps down and 75Mbps Up. • No need for GSM or CDMA • One standard

5G

Much faster than 4G, up to 100x faster. • May hit speeds of 20Gbps • Used to stream large amounts of data such as digital video and movies. • Low -latency links

Steps for bluetooth

Enable Bluetooth • Enable pairing • Find a device for pairing • Enter the appropriate PIN code • Test connectivity

Mobile device management

Corporate email configuration • Two-factor authentication • Corporate applications