Understanding how common technologies work at a basic level.
Why This Matters
Knowing how technology works helps you:
- Make informed purchasing decisions
- Troubleshoot basic problems
- Recognize misleading marketing claims
- Appreciate modern engineering
- Stay safer online and with devices
- Explain things to children
Electricity in Your Home
How Electricity Reaches You
| Stage | What Happens |
|---|
| Generation | Power plant converts energy to electricity |
| Transmission | High voltage lines carry electricity long distances |
| Substation | Voltage reduced for local distribution |
| Distribution | Local lines carry to neighborhoods |
| Transformer | Voltage reduced to 120V/240V for homes |
| Meter | Measures usage for billing |
Basic Electrical Concepts
| Concept | What It Is | Analogy |
|---|
| Voltage (V) | Electrical pressure | Water pressure |
| Current (A) | Flow of electrons | Water flow rate |
| Resistance (Ohms) | Opposition to flow | Pipe narrowness |
| Power (W) | Rate of energy use | Work being done |
Relationship: Power = Voltage x Current (Watts = Volts x Amps)
Household Electricity
| Term | Meaning |
|---|
| AC (Alternating Current) | Oscillates at 50 or 60 cycles per second depending on country |
| Circuit breaker | Cuts power if too much current flows |
| Ground | Safety path for stray electricity |
| GFCI outlet | Cuts power if current leaks (bathroom, kitchen) |
Common Appliance Power
| Appliance | Typical Power |
|---|
| LED bulb | 10W |
| Laptop | 50W |
| TV | 100-200W |
| Refrigerator | 150W (running) |
| Microwave | 1000-1500W |
| Hair dryer | 1500W |
| Electric oven | 2000-5000W |
Batteries
How Batteries Work
| Component | Role |
|---|
| Anode | Negative terminal, releases electrons |
| Cathode | Positive terminal, receives electrons |
| Electrolyte | Allows ion flow between terminals |
| Chemical reaction | Produces electrons (electricity) |
Battery Types
| Type | Chemistry | Rechargeable | Common Uses |
|---|
| Alkaline | Zinc/Manganese dioxide | No | Remotes, flashlights |
| Lithium-ion | Lithium compounds | Yes | Phones, laptops |
| Lead-acid | Lead/Sulfuric acid | Yes | Car batteries |
| NiMH | Nickel/Metal hydride | Yes | Rechargeable AAs |
Battery Care
| Practice | Reason |
|---|
| Avoid extreme temperatures | Damages chemistry, reduces life |
| Don't fully discharge Li-ion | Degrades battery |
| Store partially charged | Best for long-term storage |
| Use correct charger | Wrong voltage can damage or cause fire |
Screens and Displays
How LCD Screens Work
| Layer | Function |
|---|
| Backlight | Provides light |
| Polarizing filter | Aligns light waves |
| Liquid crystals | Twist to block/pass light |
| Color filters | Create red, green, blue subpixels |
| Second polarizer | Final light control |
Display Technologies
| Technology | How It Works | Pros/Cons |
|---|
| LCD | Backlight through liquid crystals | Affordable, good brightness |
| OLED | Each pixel emits own light | Perfect blacks, thin, more expensive |
| LED TV | LCD with LED backlight | Better contrast than old LCD |
| QLED | LCD with quantum dot enhancement | Bright, good color |
Resolution
| Resolution | Pixels | Common Name |
|---|
| 1920 x 1080 | ~2 million | 1080p, Full HD |
| 2560 x 1440 | ~3.7 million | 1440p, 2K |
| 3840 x 2160 | ~8 million | 4K, Ultra HD |
| 7680 x 4320 | ~33 million | 8K |
Internet and Networking
How Data Travels
| Step | What Happens |
|---|
| Your device | Converts data to signals |
| Router | Directs traffic, provides address |
| Modem | Converts to signal for your connection type |
| ISP network | Routes through their infrastructure |
| Internet backbone | High-capacity global network |
| Destination server | Receives and responds |
Connection Types
| Type | Technology | Speed Range |
|---|
| DSL | Phone lines | 5-100 Mbps |
| Cable | Coax cable | 50-1000 Mbps |
| Fiber | Light through glass | 100-10000 Mbps |
| 5G | Cellular | 50-1000+ Mbps |
| Satellite | Orbiting satellites | 25-500 Mbps |
WiFi Basics
| Term | Meaning |
|---|
| Router | Device that creates network |
| SSID | Network name |
| Band (2.4/5 GHz) | Frequency; 5GHz faster but shorter range |
| Channel | Specific frequency slice |
| Encryption (WPA3) | Security protocol |
Internet Speed
| Term | Meaning | Typical Needs |
|---|
| Mbps | Megabits per second | 25 Mbps for streaming HD |
| Latency/Ping | Response time | Low for gaming (<50ms) |
| Bandwidth | Total capacity | Shared among devices |
| Download | Data to you | Most common measure |
| Upload | Data from you | Important for video calls |
How Computers Work
Basic Components
| Component | Function |
|---|
| CPU | Processes instructions, "brain" |
| RAM | Short-term memory, fast |
| Storage (SSD/HDD) | Long-term memory, keeps data |
| GPU | Graphics processing |
| Motherboard | Connects all components |
| Power supply | Converts AC to DC power |
How Software Runs
| Level | What It Is |
|---|
| Machine code | Binary (1s and 0s) CPU understands |
| Operating system | Manages hardware and programs |
| Applications | Programs you use |
| Files | Data stored on drive |
Storage Comparison
| Type | Technology | Speed | Durability |
|---|
| HDD | Spinning disk | Slower | Moving parts fail |
| SSD | Flash memory | Fast | No moving parts |
| NVMe | Advanced flash | Very fast | Most expensive |
Smartphones
Key Components
| Component | Function |
|---|
| SoC (System on Chip) | CPU, GPU, modem in one chip |
| Display | Touch screen (capacitive) |
| Battery | Lithium-ion power |
| Cameras | Image sensors |
| Sensors | Accelerometer, gyroscope, GPS |
| Antennas | Cellular, WiFi, Bluetooth, NFC |
How Touch Screens Work
| Type | Technology |
|---|
| Capacitive | Detects electrical conductivity of finger |
| Multitouch | Multiple contact points tracked |
| Pressure | Force touch detects pressure level |
Cellular Networks
| Generation | Speed | Key Feature |
|---|
| 2G | 50 kbps | Digital voice, text |
| 3G | 2 Mbps | Mobile internet |
| 4G LTE | 100 Mbps | Streaming video |
| 5G | 1+ Gbps | Low latency, IoT |
Cameras
Digital Camera Basics
| Component | Function |
|---|
| Lens | Focuses light |
| Sensor | Converts light to electrical signal |
| Processor | Converts signal to image file |
| Storage | Saves image files |
Key Terms
| Term | Meaning |
|---|
| Megapixels | Millions of pixels in image |
| Aperture (f-stop) | Size of lens opening, affects light and depth |
| Shutter speed | How long sensor is exposed |
| ISO | Sensor sensitivity (higher = more grain) |
| Focus | Sharpness on subject |
Sensor Size
| Sensor | Size | Found In |
|---|
| Full frame | 36 x 24 mm | Professional cameras |
| APS-C | 22 x 15 mm | Enthusiast cameras |
| Micro 4/3 | 17 x 13 mm | Mirrorless cameras |
| 1 inch | 13 x 9 mm | Premium compacts |
| Phone sensor | 6 x 4 mm | Smartphones |
Larger sensors: Better low-light performance, more background blur.
Audio Technology
How Speakers Work
| Step | What Happens |
|---|
| Electrical signal | Represents sound wave |
| Voice coil | Creates magnetic field |
| Interaction | Magnet repels/attracts coil |
| Cone movement | Pushes air, creates sound |
| Format | Compression | Quality |
|---|
| WAV/FLAC | None/Lossless | Full quality, large files |
| MP3 | Lossy | Good quality, small files |
| AAC | Lossy | Better than MP3 at same size |
| Streaming | Various | Quality depends on bitrate |
Bluetooth
| Version | Key Feature |
|---|
| 4.0 | Low energy (BLE) |
| 5.0 | Longer range, faster |
| Codecs | aptX, LDAC improve audio quality |
Medical Technology
| Tool | How It Works |
|---|
| X-ray | Radiation passes through body, absorbed differently by tissues |
| CT scan | Multiple X-rays create 3D image |
| MRI | Magnetic fields affect hydrogen atoms |
| Ultrasound | Sound waves bounce off tissues |
| ECG/EKG | Measures heart's electrical activity |
Thermometers
| Type | Technology |
|---|
| Digital | Electrical resistance changes with temperature |
| Infrared | Detects heat radiation |
| Mercury/Alcohol | Liquid expands with heat |
GPS Navigation
How GPS Works
| Step | What Happens |
|---|
| Satellites | 30+ orbit Earth, broadcast signals |
| Your device | Receives signals from multiple satellites |
| Time calculation | Distance = signal travel time x speed of light |
| Triangulation | 4+ satellites pinpoint location |
| Accuracy | Usually within a few meters |
GPS Facts
| Fact | Detail |
|---|
| Satellites needed | Minimum 4 for 3D position |
| Accuracy | 3-5 meters typically |
| Works indoors? | Usually not; signal blocked |
| Free to use | US government provides signal |
Key Takeaways
Electricity is electron flow - Voltage pushes, current flows, resistance opposes
Batteries store chemical energy - Reactions release electrons as electricity
Screens control light - LCD blocks backlight; OLED pixels emit light
Internet is packet-switched - Data broken into pieces, routed, reassembled
Computers run on binary - Everything reduces to 1s and 0s
Touch screens detect conductivity - Your finger completes electrical circuits
Cameras capture light digitally - Sensor converts photons to electrical signals
Speakers move air - Magnets push cones to create pressure waves
GPS uses precise timing - Signal travel time reveals distance from satellites
Knowing basics helps troubleshooting - Understanding how things work helps fix them