Unit 04
⚡ Logic & Circuits
Fundamental of
Digital Circuits
Understand how physical computers are built from simple logic gates. From basic NOT/AND/OR gates through to universal NAND/NOR gates, Boolean algebra simplification, Karnaugh maps, combinational adder circuits and sequential flip-flop memory elements — the building blocks of every CPU. Covers competency levels 4.1–4.4 from the NIE ICT syllabus.
🔲 NOT Gate
🔲 AND Gate
🔲 OR Gate
🔲 XOR Gate
🔲 NAND Gate
🔲 NOR Gate
🔲 XNOR Gate
🌐 Universal Gates
📐 Boolean Algebra
⚖️ De Morgan's Laws
🗺️ Karnaugh Map
📋 SOP & POS Forms
➕ Half Adder
➕ Full Adder
🔁 Flip-Flops
📚 Competency Levels — Unit 04
COMPETENCY 4.1 · 6 PERIODS
Basic Logic Gates
Basic gates: NOT, AND, OR, XOR. Combinational gates: NAND, NOR, XNOR. Universal gates: NAND and NOR. Truth tables for up to 3 inputs. Fabricating any gate using universal gates.
COMPETENCY 4.2 · 8 PERIODS
Boolean Algebra & Simplification
Postulates, commutative, associative, distributive, identity and redundancy laws. De Morgan's theorems. SOP and POS standard forms. Simplification using Boolean theorems and Karnaugh map.
COMPETENCY 4.3 · 6 PERIODS
Digital Circuit Design
Designing logic circuits for real-world applications (up to 3 inputs). Identifying day-to-day situations requiring logic circuits, creating truth tables, deriving expressions and drawing circuits.
COMPETENCY 4.4 · 6 PERIODS
Adders & Flip-Flops
Half adder and full adder — truth tables and logic expressions. Feedback loops for storing bits. Flip-flops as the basis of sequential memory circuits inside the CPU.
⚡ Logic Gate Truth Tables — Quick Reference
NOT
Y = Ā
| A | Y |
|---|---|
| 0 | 1 |
| 1 | 0 |
AND
Y = A · B
| A | B | Y |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
OR
Y = A + B
| A | B | Y |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 1 |
XOR
Y = A ⊕ B
| A | B | Y |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
NAND
Y = A · B̄
| A | B | Y |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
NOR
Y = A + B̄
| A | B | Y |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
Half Adder
Sum=A⊕B | Carry=A·B
| A | B | Sum | Carry |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 0 | 1 | 1 | 0 |
| 1 | 0 | 1 | 0 |
| 1 | 1 | 0 | 1 |
XNOR
Y = A ⊙ B
| A | B | Y |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
📥 Unit 04 — Available Downloads
📄
Full Notes — Digital Circuits
PDF · 4.5 MB · 62 pages
📄
Logic Gates & Truth Tables
PDF · 1.1 MB · 10 pages
📄
Boolean Algebra Laws & Theorems
PDF · 1.3 MB · 12 pages
📄
Karnaugh Map Worksheet
PDF · 1.0 MB · 10 pages
📄
Half Adder & Full Adder Notes
PDF · 0.9 MB · 8 pages