Module 3 — Hardware

Module 3 · week of 09/08/2026 · Tech+: Hardware (Lesson 1 Computer Hardware) — CPU, memory, storage, peripherals, ports. · Download .docx

Objectives

Explain how the fundamental components of computer systems interact to perform essential functions.
Compare and contrast types of computers and application software.

Key terms

CPU: Central processing unit — the chip that executes program instructions.
ALU: Arithmetic logic unit — the part of the CPU that does math and comparisons.
Control unit: The part of the CPU that fetches instructions and directs the other parts.
Clock speed: How many cycles per second the CPU runs, measured in gigahertz (GHz).
Core: An independent processing unit inside a CPU; multi-core CPUs run several tasks at once.
RAM: Random access memory — fast, temporary, volatile working memory.
Volatile: Memory that loses its contents when power is turned off (RAM).
Non-volatile: Storage that keeps its contents without power (SSD, hard drive, flash).
Hard disk drive (HDD): Storage that records data magnetically on spinning platters — large and inexpensive.
Solid-state drive (SSD): Storage that uses flash memory chips — fast, quiet, no moving parts.
Byte: Eight bits; the unit used to measure file size and storage (KB, MB, GB, TB).
Motherboard: The main circuit board that connects the CPU, memory, storage, and ports.
Peripheral: A device connected to the computer — keyboard, mouse, printer, monitor, webcam.
USB: Universal Serial Bus — the standard port for connecting peripherals and charging.
Moore's Law: The observation that transistor counts on chips double about every two years.

The concept

The CPU (central processing unit) executes instructions. Its control unit fetches and decodes; its arithmetic logic unit (ALU) does the math and comparisons.

CPU speed is measured in gigahertz (GHz) — billions of cycles per second. More cores let the CPU work on more tasks at once.

RAM (random access memory) is fast, temporary working memory. It is volatile — everything in it disappears when the power goes off. More RAM = more programs open without slowing down.

Storage is permanent (non-volatile): hard disk drives (spinning platters, cheap, large), solid-state drives (flash memory, fast, no moving parts), USB flash drives, optical discs, and cloud storage.

Units: 8 bits = 1 byte. 1 KB ≈ 1,000 bytes; 1 MB ≈ 1,000 KB; 1 GB ≈ 1,000 MB; 1 TB ≈ 1,000 GB. A photo is a few MB; a movie is a few GB.

The motherboard is the main circuit board that connects CPU, RAM, storage, and ports. The power supply converts wall power to the low-voltage DC the parts need.

Input devices: keyboard, mouse, touchscreen, microphone, camera, scanner. Output devices: monitor, printer, speakers, projector. Some are both (touchscreen, headset).

Ports and connections: USB (most peripherals), HDMI (video), Ethernet (wired network), Bluetooth and Wi-Fi (wireless), Thunderbolt/USB-C (fast data and charging).

Moore's Law: the number of transistors on a chip roughly doubles every two years — why devices keep getting faster, smaller, and cheaper.

Module 3 items: Hardware Assignment (50) and Module 3 Quiz (20).

Worked examples

Example 1: A student's laptop slows to a crawl with 20 browser tabs open, but files still open fine. RAM problem or storage problem? — RAM — running programs and tabs live in working memory. Storage holds saved files. Fix: close tabs or add RAM; the storage drive is not the bottleneck.

Example 2: Two laptops: 8 GB RAM / 1 TB HDD vs 8 GB RAM / 256 GB SSD. Same price. Which boots and opens apps faster? Which holds more? — The SSD laptop is faster (flash memory, no moving parts). The HDD laptop holds four times as much. Trade-off: speed vs capacity.

Example 3: On the board: 3 GB movie, 4 MB photo, 40 KB essay. How many photos fit in the space of one movie? — 3 GB = 3,000 MB; 3,000 ÷ 4 = 750 photos. The essay is tiny — 4 MB = 4,000 KB = 100 essays per photo.

Common mistakes

"More storage makes my computer faster." Running programs live in RAM. Storage holds saved files. A full RAM, not a full drive, is what slows a laptop with 20 tabs open.
"RAM keeps my work when I turn the computer off." RAM is volatile — everything in it disappears when the power goes off. Storage (SSD, HDD, flash) is non-volatile.
"A bit and a byte are the same thing." 8 bits = 1 byte. Then 1 KB ≈ 1,000 bytes, 1 MB ≈ 1,000 KB, 1 GB ≈ 1,000 MB, 1 TB ≈ 1,000 GB.

Self-check

Try each one before you look. A miss here costs nothing and tells you exactly what to reread.

1. Which component is often called the brain of the computer because it carries out instructions?

2. What happens to the contents of RAM when the computer loses power?

3. How many bits are in one byte?

4. Which is the largest unit of storage?

5. Which device is an input device?

Canvas is the official record. This companion enhances the PGCC curriculum; it does not replace it. Last name and class year only. Students with a 504 plan or IEP: your accommodations apply.

↑ Back to top