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: 17
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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Welcome, students! Today, we are diving deeper into the exciting world of digital electronics. We have already learned about basic logic gates, the building blocks of all digital devices. Now, we will see how these gates are combined to perform useful tasks in what we call combinational logic circuits. We will then explore a powerful device that uses these principles: the microcontroller. This topic is incredibly relevant to our lives in Ghana. The smartphone you use for mobile money (MoMo), the traffic lights in Accra or Kumasi, and even modern agricultural systems all rely on the principles we will learn today.
Part 1: Combinational Logic Circuits
A. What is a Combinational Logic Circuit?
A combinational logic circuit is a type of digital circuit where the output at any given time depends *only* on the combination of inputs at that exact same time. Key Characteristic: They have no memory. The circuit does not remember past inputs. Once the inputs change, the output changes accordingly. Analogy: Think of a simple calculator. When you press `2 + 3 =`, the output is `5`. It doesn't matter if you calculated `1 + 1` before. The current output `5` depends only on the current inputs `2` and `3`.
These circuits are built by combining basic logic gates like AND, OR, NOT, NAND, NOR, and XOR.