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: 16
Grade code: 2.3.3.LI.4
Strand code: 3
Sub-strand code: 3
Content standard code: 2.3.3.CS.2
Indicator code: 2.3.3.LI.4
Theme: ELECTRIC FIELD, MAGNETIC FIELD AND ELECTRONICS
Subtheme: DIGITAL ELECTRONICS
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In today's world, we are surrounded by "smart" devices: mobile phones, computers, digital watches, traffic lights, and even our prepaid ECG meters. How do these devices make decisions? The answer lies in digital electronics. Unlike analog signals which can have any value (like the volume knob on an old radio), digital signals have only two states: ON or OFF, represented by the numbers 1 and 0. This lesson introduces the fundamental building blocks of all digital devices: Logic Gates. These are like tiny decision-making circuits.
A. Analog vs. Digital Signals
Before we discuss logic gates, we must understand the type of information they work with. Analog Signal: A signal that is continuous and can have an infinite number of values within a range. Example in Ghana: The dimmer switch for a ceiling fan. You can set the fan speed to many different levels between low and high. The sound waves from someone speaking are also analog. Visual: Digital Signal: A signal that is discrete and can only have a limited number of values, typically two: ON (HIGH) and OFF (LOW). In electronics, we represent these two states using the binary number system: HIGH (e.g., +5 Volts) = 1 LOW (e.g., 0 Volts) = 0 Example in Ghana: A simple light switch in your classroom. It is either ON (1) or OFF (0). There is no in-between. Visual:
All modern computers, phones, and smart devices use digital signals because they are more reliable and less affected by noise. B. What are Logic Gates?