Unit 4020 Digital Principles (J/651/0739) Assignment Brief 2026

Unit 4020 Digital Principles Assignment Brief

Introduction

While the broad field of electronics covers many aspects, it is digital electronics which now has the greatest impact. This is immediately evident in the mobile phone, laptop, and numerous other everyday devices and systems. Digital electronics allows us to process, store, and transmit data in digital form in robust ways, which minimises data degradation.

The unit introduces digital principles and the two main branches of digital electronics, combinational and sequential. Thus, the student gains familiarity in the fundamental elements of digital circuits, notably different types of logic gates and bistables. The techniques by which such circuits are analysed, introduced, and applied, including Truth Tables, Boolean Algebra, Karnaugh Maps, and Timing Diagrams.

The theory of digital electronics has little use unless the circuits can be built – at low cost, high circuit density, and in large quantity. Thus, the key digital technologies are introduced. These include the conventional TTL (Transistor-Transistor Logic) and CMOS (Complementary Metal Oxide Semiconductor). Importantly, the unit moves on to programmable logic, including the Field Programmable Gate Array (FPGA). Finally, some standard digital subsystems, which become important elements of major systems such as microprocessors, are introduced and evaluated.

On successful completion of this unit students will have a good grasp of the principles of digital electronic circuits, and will be able to proceed with confidence to further study.

Learning Outcomes

LO1 Explain combinational logic circuits

LO2 Interpret sequential logic circuits

LO3 Describe the technologies used to implement digital electronic circuits

LO4 Analyse a range of digital subsystems, hence establishing the building blocks for larger systems.

Essential Content

LO1 Explain combinational logic circuits

Concepts and applications:

• Digital principles, logic design and logic circuits, real-world applications, and history and future trends.

Concepts of combinational logic:

• Logic circuits implemented with electro-mechanical switches and transistors. Circuits built from AND, OR, NAND, NOR, XOR gates to achieve logic functions, e.g. majority voting, simple logical controls, adders.

Number systems, and binary arithmetic:

• Binary, Decimal, Hexadecimal number representation, converting between, applications and relative advantages. Addition and subtraction in binary, range of n-bit numbers.

Analysis of logic circuits:

• Truth Tables, Boolean Algebra, de Morgan’s theorem, Karnaugh Maps Simplification and optimisation of circuits using these techniques.

LO2 Interpret sequential logic circuits

Sequential logic elements and circuits:

• SR latch built from NAND or NOR gates
• Clocked and edge-triggered bistables, D and JK types
• Simple sequential circuits, including shift registers and counters
• Timing Diagrams.

Memory technologies:

• Memory terminology, overview of memory technologies including Static RAM, Dynamic RAM and Flash memory cells
• Relative advantages in terms of density, volatility and power consumption
• Typical applications, e.g., in memory stick, mobile phone, laptop.

LO3 Describe the technologies used to implement digital electronic circuits

Logic values represented by voltages: The benefit of digital representation of information The concept of logic input and output values and thresholds. Digital technologies:

• Introduction to discrete logic families, CMOS and TTL, relative advantages in terms of speed, power consumption, density
• Programmable logic, FPGAs, relative advantages and applications
• Practical applications and the future of digital technologies.

LO4 Analyse a range of digital subsystems, hence establishing the building blocks for larger systems

User interface:

• Examples to include switches, light emitting diodes and simple displays

Digital subsystems:

• Examples to be drawn from adders (half, full, n-bit), multiplexers and demultiplexers, coders and decoders, counters applied as timers, shift registers applied to serial data transmission, elements of the ALU (Arithmetic Logic Unit). Emphasis on how these can be applied, and how they might fit into a larger system.

Learning Outcomes and Assessment Criteria

Activity

Holistically, you are required to design combinational logic circuits by making best use of Truth, Tables, Boolean Alegeba and Karnaugh Map. Following the steps below should help with this.

1. Explain what is meant by a combinational logic circuit?

2. You have been assigned to a ‘P’ column in Table 1 below. Write down the Boolean equation for the P that was assigned to you.

3. Use a K-map to see if the Boolean output from the P value can be minimised. Here, you should group the 1’s only for a sum of products result. Show all evidence of K map use. You may use proofing tools provided all work has been completed from first principles.

(~200 words)

4. Your line manager has asked you to analyse a 3-input majority vote taker (the same circuit could be used in a Car for error checking). This will be for three ‘participants’ and such that it will illuminate an LED if two or more vote yes (a logic ‘1’). Otherwise, if there is no majority vote, the LED should remain off. You are expected to write down the truth table and from that write down the Boolean output.

5. By using a Karnaugh map, optimise (minimise) your initial design.

6. Use De-Morgan’s Theorem to design a NAND only solution. Show all working.

7. Verify that this design works in Multisim. Include evidence.

8. List at least one advantage of using De-Morgan’s Theorem.

(~300 words)