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: 19
Grade code: 2.5.2.LI.10
Strand code: 4
Sub-strand code: 2
Content standard code: 2.5.2.CS.1
Indicator code: 2.5.2.LI.10
Theme: ELECTRICAL AND ELECTRONIC TECHNOLOGY
Subtheme: ELECTRONIC COMPONENTS AND CIRCUITS
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This lesson introduces the fundamental concept of modulation, which is the backbone of all wireless communication. We will explore how the sound from a radio presenter at Peace FM in Accra can be transmitted wirelessly to a radio in a village near Wa, or how our mobile phone calls travel through the air. Understanding modulation is key to appreciating how radio, television, mobile phones, and Wi-Fi work. It is a critical principle that turns our voices and data into signals that can travel over vast distances.
This lesson will be delivered using a mix of direct instruction, visual aids (diagrams on the board), and collaborative group discussions as suggested by the NaCCA pedagogy. A. The Carrier Wave: The "Delivery Truck" of Communication
Imagine you want to send a letter from Accra to Kumasi. You can't just throw the letter into the air and hope it gets there. You need to put it on a vehicle—a bus, a trotro, or a cargo truck—that is strong enough to make the long journey.
In electronics, the carrier wave is like that delivery truck. Definition: A carrier wave is a high-frequency, constant-amplitude electromagnetic wave that is used to "carry" a lower-frequency information signal (like voice or music) from a transmitter to a receiver. Properties: High Frequency: It oscillates very quickly. This allows it to travel long distances efficiently and use smaller, practical antennas. Constant Amplitude: Its strength or "height" does not change on its own. Constant Frequency: The number of waves per second does not change on its own. Purpose: By itself, a carrier wave contains no useful information. Its only job is to be the transport medium for the actual message.
*Visual Representation on the Board:* ``` Amplitude ^ | /\ /\ /\ /\ | / \ / \ / \ / \ --|---/----\----/----\----/-----> Time | / \/ \/ \ | / |/ ``` *(A simple, clean sine wave representing the high-frequency, constant-amplitude carrier wave.)* B. Modulation: Putting the Message on the Truck