Lesson Notes By Weeks and Term v4 - SHS 2
DIGITAL ELECTRONICS
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DIGITAL ELECTRONICS
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Subject: Physics
Class: SHS 2
Term: 2nd Term
Week: 18
Grade code: 2.3.3.LI.2
Strand code: 3
Sub-strand code: 3
Content standard code: 2.3.3.CS.2
Indicator code: 2.3.3.LI.2
Theme: ELECTRIC FIELD, MAGNETIC FIELD AND ELECTRONICS
Subtheme: DIGITAL ELECTRONICS
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This lesson introduces the fundamental building blocks of all modern digital devices: logic gates. Every smartphone, computer, traffic light, and digital watch, no matter how complex, operates based on the simple "decision-making" circuits we will study today. We will explore how these gates process information using a simple binary system (on/off, true/false) and learn to represent their behaviour using symbols and truth tables. Understanding these concepts is the first step to understanding the language of modern technology.
A. Digital vs. Analogue Signals
Before we talk about gates, we must understand the type of information they use. In electronics, there are two types of signals: Analogue Signal: A continuous signal that can have any value within a range. Think of the volume knob on an old radio or a dimmer switch for a light bulb – you can set it to any level. Digital Signal: A signal that can only have specific, discrete values. In digital electronics, we use a binary system with only two values: HIGH (represented by the number 1), which can mean "ON", "True", or "+5V". LOW (represented by the number 0), which can mean "OFF", "False", or "0V".
Logic gates are called "digital" because they work with these HIGH (1) and LOW (0) signals. B. What is a Logic Gate?
A logic gate is a basic electronic circuit with one or more inputs and only one output. It performs a specific logical function on its inputs to determine the state of its output. Think of it as a tiny decision-maker or a gatekeeper that only lets a signal pass (produces a HIGH output) if certain conditions are met. C. What is a Truth Table?