Unit 20:  Digital Principles

Unit code                           T/615/1494

Unit level                           QCF Level 4/ NFQ Level 6

Credit value                       15


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 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 are 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

By the end of this unit students will be able to:

  1. Explain and analyse simple combinational logic circuits.
  2. Explain and analyse simple sequential logic circuits.
  3. Describe and evaluate the technologies used to implement digital electronic circuits.
  4. Describe and analyse a range of digital subsystems, hence establishing the building blocks for larger systems.