Lesson Notes By Weeks and Term v4 - SHS 3
ELECTRONIC COMPONENTS AND CIRCUITS
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ELECTRONIC COMPONENTS AND CIRCUITS
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Subject: Applied Technology
Class: SHS 3
Term: 2nd Term
Week: 18
Grade code: 2.5.2.LI.9
Strand code: 4
Sub-strand code: 2
Content standard code: 2.5.2.CS.1
Indicator code: 2.5.2.LI.9
Theme: ELECTRICAL AND ELECTRONIC TECHNOLOGY
Subtheme: ELECTRONIC COMPONENTS AND CIRCUITS
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Welcome, future engineers and innovators! Today, we are diving into the brain of every modern electronic device you use – from your mobile phone and television to the traffic lights in our cities like Accra and Kumasi. These devices make complex decisions based on simple "yes" or "no" logic. We will learn about the fundamental building blocks of this logic, called Logic Gates. Understanding logic gates is the first step to designing and building intelligent electronic systems that can solve real-world problems in our communities. This knowledge is not just for exams; it is the foundation for careers in electronics, computer engineering, and automation.
2.1 What are Logic Gates?
In digital electronics, information is represented by two voltage levels: HIGH (usually +5V), which represents the number 1 (or "True"). LOW (usually 0V or Ground), which represents the number 0 (or "False").
A logic gate is a basic electronic circuit that performs a logical operation on one or more binary inputs to produce a single binary output. Think of them as electronic decision-makers. 2.2 Basic Logic Gates
a) The AND Gate Function: The AND gate gives a HIGH (1) output only when ALL its inputs are HIGH (1). Analogy: Think of two light switches connected in series to a bulb. The bulb will only light up (HIGH output) if Switch A AND Switch B are both ON (HIGH input). Symbol: Boolean Expression: `Q = A . B` or `Q = AB` (Read as "Q equals A AND B") Truth Table: | Input A | Input B | Output Q | | :---------: | :---------: | :----------: | | 0 | 0 | 0 | | 0 | 1 | 0 | | 1 | 0 | 0 | | 1 | 1 | 1 |