Welcome to my digital world
can you find on this web site?
This web site is intended to be of interest to digital circuit designers
and students of digital circuit design. I have included a range of topics from an article
for the celebrated bystander in the street to something I hope will be of interest to the
serious designer, whether student or professional. The articles button on the panel will
take you to an introduction to all the articles. There are a few links to miscellaneous
non technical pages in the panel on the left.
The articles that you can read on this site are arranged in roughly three
groups. There are tutorial articles on Boolean algebra, including the article for the
casual bystander, practical project oriented articles and articles with a more theoretical
content. You can go directly to any of the three streams of articles through the buttons
on the left of the screen.
You can read an introductory article on Boolean Algebra. This article is
intended to provide the background required for the remaining articles. One omission from
this articles is a discussion of binary numbers. Most beginning books on digital design
give the necessary explanation of number systems. The Boolean algebra article became too
long for a single page and I have split it over two pages. You can go directly to the Boolean Algebra Page 1.
A natural progression of ideas after establishing the concept of Boolean
algebra is to consider what happens when feedback is applied within a combinatorial
circuit. The page on asynchronous logic demonstrates that memory is created in the
circuit. The combination of logic and memory allows the circuit to make decisions and
determine its response to a sequence of external events. This is the beginning of
intelligence and automation in a machine. You can go directly to the Intelligent
If exclusive-OR logic is new to you you should read the Boolean algebra
pages first to discover that Boolean algebra actually consists of at least three complete
algebras two of which are described in some detail for the design of digital circuits. The
third complete algebra is described briefly. These are termed the inclusive-OR and the
exclusive-OR algebras. Someone asked my why would you need exclusive-OR algebra? Good
question, why would you leave out a significant part of the subject?
Buy a Book or Project PC Board?
There are two items that you can buy from
this web site:
1. If you are an electronics enthusiast you
can buy one of my project boards. These boards are especially designed for students,
enthusiasts or even beginning digital engineers. Follow this link to see how you can
create projects quickly with one of these project boards. I have very few of these boards
left so you might be out of luck, unless you want a substantial number of them.
2. Buy the second edition of the book
entitled: "Introduction to Digital Circuit Theory" (ISBN: 978-0-9581894-1-5).
The book is in the form of a monograph with comb binding, card back and clear cover in A4
format. The current revision includes a number of inadvertent error corrections. The
single copy price is $39.95 (Australian dollars), which includes all currency fees and
airmail charges if purchased with the Buy Now button. PayPal
will carry out the conversion of your currency to Australian currency in a secure
transaction and e-mail me your order. Please follow this link
if you would prefer
alternative arrangements to purchasing the book:
What is Programmable Logic?
Programmable logic is a system for encapsulating your digital circuitry
into a programmable integrated circuit device without you having to leave your PC.
The Altera system offers a comprehensive and powerful integrated windows
based development environment, which includes editors (graphical and text), simulators
(full timing and functional analysis), a compiler and all required support facilities such
as programming software and error message windows. The Altera system supports a large
range of fully reprogrammable devices and device styles including in-system programmable
devices from small (300 useable gates) up to very large devices (1,000,000 and more
Xilinx Inc. are an alternative source of programmable logic devices with
much the same capabilities as the Altera devices. However, their CoolRunner range of low
power consumption devices are unmatched for portable applications. (CoolRunner is a trade
mark of Xilinx Inc.)
Take a course
If you live in South Australia and are contemplating studying electronics you can take
a course in Digital Circuit Design, including theory and hands on practice with
programmable logic devices, at either Regency Institute of TAFE or Torrens Valley
Institute of TAFE, both in South Australia. Go to the links page to visit either of these
Any questions or comments?
If you have any questions on the subject of any of the papers or would like to comment
on them you can contact me through my e-mail link shown below.
If you have a web site similar to this one, let me know the URL and I will
add it to my links page or one of my other pages. I am happy to talk to fellow
Some of the comments and sometimes critical comments that I have received have been
very helpful in enabling me to improve my material. Many thanks to the people that have
communicated with me.
Press buttons for: Links OR
Top of the page OR Articles page:
ÓDavid N. Warren-Smith, CPEng
PO Box 647, Elizabeth, South Australia 5112
22 November 2009