course: Computer Science 3 - Digital Circuits

teaching methods:
lecture with tutorials
overhead transparencies, computer based presentation, black board and chalk
responsible person:
Prof. Dr.-Ing. Jürgen Oehm
Prof. Dr.-Ing. Jürgen Oehm (ETIT), M. Sc. Lukas Straczek (ETIT), M. Sc. Dominik Veit (ETIT)
offered in:
winter term

dates in winter term

  • start: Thursday the 10.10.2019
  • lecture Thursdays: from 08:15 to 09.45 o'clock in HGA 10
  • tutorial Fridays: from 08:30 to 10.00 o'clock in HID


All statements pertaining to examination modalities (for the summer/winter term of 2020) are given with reservations. Changes due to new requirements from the university will be announced as soon as possible.
Form of exam:schriftlich + studienbegleitend
Registration for exam:FlexNow
Room : HID


The students acquire comprehensive knowledge of the subject areas Boolean algebra, structure and modes of action of basic digital circuits, cost optimization of digital functional groups, structure and functioning of basic functionalities that are particularly central components of microprocessor systems (such e.g. counter structures, shift register, ALU, bus driver, memory). Furthermore, central knowledge of the internal circuit design of current logic families are mediated, in particular, the concept and operation of CMOS logic circuits, the scaling properties of modern CMOS technologies, and the associated effects on the properties of current equipment and systems. With this know-how the students are capable of evaluating future developments in the integration technologies and therefore in digital technology itself, relating to their possibilities and limits.

The overall evaluation consists of a written exam (90%) and additional exercises (10%).


  • historical review,
  • motivation for digital-technology,
  • Boolean algebra,
  • number representation, computing circuits, arithmetic logic unit (ALU)
  • edge detector, bi-, mono- and astable circuits, flip-flops,
  • frequency divider, counter, shift register, memory,
  • diode-logic, diode-transistor-logic, transistor-transistor-logic, CMOS-logic,
  • CMOS-technology, CMOS standard-cell concept,
  • logic analysis, tools for logic analysis,
  • Moore's law.

The course starts with the theoretical foundations of Boolean algebra. Thereafter, various methods for the simplification of logical networks are presented. Next, the minimized logical networks have to be transformed into cost- respectively hardware-minimal logic circuitries. This requires that the minimized logical circuitries have to be transformed into such logical equivalent circuitries which only consist of NAND-, NOR-, and NOT-functions. Within this context it will be illustrated that the term 'costs' can represent as well the 'hardware-effort' as 'the sum of gate transit times within the critical signal paths'.

The second part of the lecture series deals with the higher rated digital function-groups. Including e.g. flip-flops, counter structures, shifting-register, multiplexer/demultiplexer, ALU and memory. The concept of synchronous/asynchronous pulse-control and parallel/sequential data-processing are discussed in accordance to the possible different architectures of higher rated function-groups.

The third part of the lecture series deals with the central characteristics of the main logic families. It starts with the historical logic families (diode-logic, diode-transistor-logic, transistor-transistor-logic) in connection with their typical attributes. Thereafter, the main attention is paid to the CMOS logic, the logic family, which comes in use mainly for all modern appliances. Against the background of the continuous advances in technology, and the features of CMOS technologies, the related impacts of technology scaling on the switching times of CMOS logik gates are illustrated.

In connection with the final presentation of the so-called Moore's law the lecture series ends with a look at possible technological developments in the future.



recommended knowledge

  • basic knowledge of electrical engineering and mathematics.



  1. Katz, Randy H. "Contemporary Logic Design", Prentice Hall, 1993
  2. Borucki, Lorenz, Stockfisch, Georg "Digitaltechnik", Teubner Verlag, 1989
  3. Pernards, Peter "Digitaltechnik I. Grundlagen, Entwurf, Schaltungen", Hüthig, 2001
  4. Fricke, Klaus "Digitaltechnik. Lehr- und Übungsbuch für Elektrotechniker und Informatiker", Vieweg, 2005
  5. Becker, Jürgen, Lipp, Hans Martin "Grundlagen der Digitaltechnik", Oldenbourg, 2005
  6. Gamm, Eberhard, Schenk, Christoph, Tietze, Ulrich "Halbleiter-Schaltungstechnik", Springer Verlag, 2016
  7. "Handbuch der Elektronik. Digitaltechnik", Medien Institut Bremen, 1999
  8. Eshragian, Karman, Eshragian, Kamran, Weste, Neil H. E. "Principles of CMOS VLSI Design: A Systems Perspective", Addison Wesley Longman Publishing Co, 1993
  9. Siemers, Christian, Sikora, Axel "Taschenbuch Digitaltechnik", Hanser Fachbuchverlag, 2002


There are tutorial sessions which accompany the lecture series. The dates will be determined later.

Virtual machine for lecture

The virtual machine for the lecture series can be downloaded here: