Understanding Digital Systems
Digital Systems
An electronic system that uses binary signals, i.e. 0 or 1, on or off.
Binary is the foundation of digital systems because it aligns with the physical reality of electronic circuits, which can easily represent two states: high voltage (1) and low voltage (0).
Boolean Algebra
Boolean algebra
A logic-based mathematical system where variables are either “true” (1) or “false” (0), used to analyse and design digital circuits.
Basic Operations
AND Gate
A basic digital logic gate that gives a high output (1) only when all inputs are high (1). It has two or more inputs and one output.
- Function - Outputs 1 if both inputs are 1.
- Example - A ⋅ B
OR Gate
A digital logic gate that gives a high output (1) if at least one input is high (1). It only outputs low (0) when all inputs are low (0).
- Function - Outputs 1 if at least one input is 1
- Example - A + B
NOT Gate
A digital logic gate that acts as a logical inverter, giving an output that is the opposite of the input: if the input is true (1), the output is false (0), and vice versa.
- Function - Inverts the input (1 → 0, 0 → 1)
- Example - ¬A or A̅
Combinational vs Sequential Logic Circuits
| Type | Description | Example |
|---|---|---|
| Combinational | Output depends only on current inputs | Logic locks, alarms |
| Sequential | Output depends on current inputs and past states | Timers, counters, memory |
