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4.3 Introduction to Digital Electronics
Electrical Technology · Grade 11 · 18 lessons in the design
What this covers
- Meaning of digital electronics and how digital systems differ from analogue systems
- Analogue and digital signals in electronic systems
- The two logic states: logic 1 (high, usually 5 V) and logic 0 (low, usually 0 V)
- Number systems used in digital electronics: decimal, binary and binary-coded decimal (BCD)
- Conversion between the decimal and binary number systems
- Binary arithmetic: addition, subtraction, ones complement and twos complement
- Basic logic functions and their gates: AND, OR and NOT
- Truth tables and Boolean expressions for basic logic functions
- Constructing simple logic circuits using switches, bulbs and gates
- Advantages and disadvantages of digital and analogue systems
- Applications and importance of logic gates in digital electronic circuits
What you will be able to do
- differentiate digital and analogue signals in electronics
- convert number systems in digital electronics
- relate the binary and decimal number system conversions to digital signals
- construct circuits to represent basic logic functions
- appreciate the use of logic gates in digital electronic circuits
Key questions
“How do digital electronics systems work?”
“How are binary numbers related to digital signals?”
Lessons
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Introduction to digital electronics
40 min · 1 practice tasks · quizIntroduce digital electronics and how it differs from analogue electronics.
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Analogue and digital signals
40 min · 1 practice tasks · quizCompare analogue and digital signals and explain the effect of noise.
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The two logic states
40 min · 1 practice tasks · quizDescribe logic 1 and logic 0 and the voltage levels that represent them.
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Decimal and binary number systems
40 min · 1 practice tasks · quizDescribe the decimal and binary number systems and their place values.
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Converting decimal to binary
40 min · 1 practice tasks · quizConvert decimal numbers into binary by repeated division.
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Converting binary to decimal
40 min · 1 practice tasks · quizConvert binary numbers into decimal using place values.
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Binary-coded decimal (BCD)
40 min · 1 practice tasks · quizCode each decimal digit as four bits in binary-coded decimal.
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Binary addition
40 min · 1 practice tasks · quizAdd binary numbers using the rules and carries.
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Binary subtraction
40 min · 1 practice tasks · quizSubtract binary numbers using borrowing.
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One's complement
40 min · 1 practice tasks · quizFind the one's complement of a binary number by inverting every bit.
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Two's complement
40 min · 1 practice tasks · quizFind the two's complement and use it to represent negative numbers.
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The AND gate
40 min · 1 practice tasks · quizDescribe the AND gate, its symbol, truth table and Boolean expression.
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The OR gate
40 min · 1 practice tasks · quizDescribe the OR gate, its symbol, truth table and Boolean expression.
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The NOT gate
40 min · 1 practice tasks · quizDescribe the NOT gate, or inverter, its symbol, truth table and expression.
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Truth tables
40 min · 1 practice tasks · quizConstruct truth tables for basic logic functions.
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Combinational logic and Boolean expressions
40 min · 1 practice tasks · quizCombine gates and evaluate simple Boolean expressions.
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Constructing logic with switches and bulbs
40 min · 1 practice tasks · quizBuild the basic logic functions with switches, a lamp and a cell.
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Applications of logic gates and digital systems
40 min · 1 practice tasks · quizExplain the uses of logic gates and the advantages of digital systems.