An overview of digital electronics, including binary number system, logic gates, and the basics of digital circuit design.
Introduction to Digital Electronics
Key concepts, building blocks, and practical considerations
1. What Is Digital Electronics?
- Definition: Branch of electronics that deals with signals having discrete (binary) values, typically 0 and 1.
- Contrast with Analog:
- Analog: Continuous range of values (e.g., voltage varies smoothly).
- Digital: Only a finite set of levels; most common is two‑level (binary) logic.
- Why It Matters
- Enables reliable data storage, processing, and transmission.
- Forms the foundation of computers, microcontrollers, communication systems, and many modern devices.
2. Binary Number System
| Decimal | Binary | Hexadecimal |
|---|---|---|
| 0 | 0 | 0 |
| 1 | 1 | 1 |
| 2 | 10 | 2 |
| 3 | 11 | 3 |
| 4 | 100 | 4 |
| … | … | … |
| 15 | 1111 | F |
| 16 | 10000 | 10 |
- Bit – a single binary digit (0 or 1).
- Nibble – 4 bits (one hexadecimal digit).
- Byte – 8 bits (common data unit).
- Word – processor‑dependent group of bits (e.g., 16‑, 32‑, 64‑bit).
3. Basic Digital Logic Levels
| Symbol | Voltage Range (Typical, 5 V TTL) | Logic State |
|---|---|---|
| 0 | 0 V – 0.8 V | LOW (Logic 0) |
| 1 | 2 V – 5 V | HIGH (Logic 1) |
Note: CMOS families use a wider range (0 V – VDD) and have lower static power consumption.
4. Fundamental Logic Gates
| Gate | Symbol | Boolean Expression | Truth Table |
|---|---|---|---|
| AND |  |
Y = A·B | 0·0=0, 0·1=0, 1·0=0, 1·1=1 |
| OR |  |
Y = A+B | 0+0=0, 0+1=1, 1+0=1, 1+1=1 |
| NOT (Inverter) |  |
Y = ¬A | 0→1, 1→0 |
| NAND |  |
Y = ¬(A·B) | Complement of AND |
| NOR |  |
Y = ¬(A+B) | Complement of OR |
| XOR |  |
Y = A⊕B |
Topic Concept Map