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I
PRODUCT SHOWCASE
I
The Electronics Workbench
This software package from Emona Instruments
is designed to enable on-screen simulation of
analog and digital circuits, complete with testing
by simulated instruments. It could be highly
effective as a teaching aid for schools and
technical colleges.
By LEO SIMPSON
One of the major problems in teaching electronics is the need to spend
large amounts of time in setting up
circuit demonstrations for or during
classes. Most circuit princi ,Jes are
best taught using theoretic l examples which can then be bacJ....ed up by
practical circuit examples. However,
the time spent setting these up can
often make this impracticable.
This Electronics Workbench package , produced by Interactive Image
Technologies of Canada, enables circuits to be simulated on the computer
screen, giving lecturers and teachers
more time to spend on other things.
Our review copy was of the profes-
sional version which provides a VGA
display and unlimited components
in a circuit. The software comes on
four floppy discs and the auto-installation system makes loading the software into your computer simple.
The Electronics Workbench comes
as two modules: analog and digital.
The analog section provides you with
four test instruments, as follows: a
voltmeter which can show volts ,
amps, ohms and dBs; a 2-channel oscilloscope which operates in a way
similar to a real one; a function generator which produces sine, triangle
and squarewave signals from lHz to
999kHz; and a Bode plotter for dis-
playing frequency responses.
Once the software is running, the
right-hand column of the screen shows
a 'parts bin' which contains the icons
to all the available parts you can use
in circuit. You have an unlimited
number of each component so you
don't have to worry about running
out of circuit parts. In fact, the limit
on circuit complexity is more a matter of computer speed rather than the
allowable number of parts; larger and
more complex circuits take longer to
simulate.
To lay out a circuit, you simply
click on the desired component with
your mouse and drag it to the desired
location on the screen. To join up
components, you move the mouse to
one of the ends of the component
until the connector of that component lights up as a small black box.
You then click and drag a connecting
wire between that component and the
next component.
Both the analog and digital sections
use the same layout procedure. The
digital section's parts bin contains all
the basic gates and flipflops, again in
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This 3-stage common emitter amplifier is one of the
sample circuits provided and has both the dual trace
CRO and the function generator connected in circuit.
Note that the CRO shows input and output traces.
56
SILICON
CHIP
i
This circuit demonstrates the software's ability to provide
Bode plots of a Wien bridge network. The right hand
column shows the analog parts available. These are
brought to the screen by clicking and dragging.
unlimited quantity. The test instruments in this section include a word
generator which can hold 16 8-bit
words; an 8-channel logic analyser;
and a truth table/symbol converter
capable of turning truth tables into
circuit representations.
This allows you to set up a digital
circuit and go through the analysis
showing all the possible states.
The package also includes what is
called a Hypertext help system, which
can be tailor-made to suit your requirements. All you do is to type the
text you wish to appear on screen in
an ASCII-format file on any wordprocessor. This feature makes it suitable for use alongside most textbooks.
Components such as op amps and
transistors are assumed to have standard parameters but you can customise
these to simulate virtually any device. One point we should make is
that this software package is not like
some of the more expensive circuit
simulation packages which have comprehensive libraries of most commercially available op amps and transistors. Instead, it is intended more as a
teaching and tutorial package rather
than for design testing simulation, although it can do this to a limited
extent.
It is not possible to link analog and
digital components together. In a classroom situation, where analog and digital electronics tends to be segregated,
this would not cause a problem but it
makes it difficult, if not impossible,
to analyse many of the circuits de-
scribed in SILICON CHIP.
Some of the supporting literature
which comes the Electronics Workbench suggests that this software package is ideal for practical classes with
students because it allows them to
build. circuits without the need for
components, test instruments and the
like, saving the school or college
money.
We hesitate to fully agree with this
because as useful as the package may
be, it cannot fully demonstrate to electronics students the practical problems that come up in circuit design
and layout; eg, earth loops in amplifier design or over-biasing a class AB
audio amplifier so that the output transistors blow up. Interestingly though,
if the input of the simulated oscilloscope is not grounded, 1 volt of 60Hz
signal is added to the output waveforms. This simulated hum pickup by
the circuit is a small but practical
point which would often be overlooked by students.
The Electronics Workbench comes
in three versions: the personal version which has a monochrome display and can run circuits with up to
30 components, and costs $149; the
personal plus version which has unlimited components, retailing at $299;
and the professional version with both
EGA and VGA capabilities for $429.
Each comes complete with a useful
reference manual which shows how
to install and operate the software, as
well as explaining briefly how the
software simulates the circuits.
-
ii
····- • .. ~- . ....
. -
Our first full catalogue of our huge
range of electronic components and
kitsets is nearing completion and will
soon be delivered to those requesting
a copy - FREE!
To secure your copy, please fill in the
coupon (or copy details), send together
with 3 x 45<1: stamps for postage and
we'll send a catalogue, hot off the
press!
You'll also receive updates, bonus
offers, specials, etc. during the year
AND each month until June you will be
in the draw for a free SCOPE PH20
soldering iron!
.::,
=:.
Q
'eLJ / Please send me a FREE catalogue
0:;)t
I have enclosed stamps for postage
Name: .
Address ..
.. . .. Postcode
,\
ALL ELECTRONIC COMPONENTS
l i 118 · 122 Lonsdale Street. Melbourne. V,c 3000
l:L.. Telephone (03)6623506 Fax (03)6633822
Our conclusion: this software could
be very useful to students and lecturers in a structured electronics course.
For further information, contact
Emona Instruments, PO Box 15,
Camperdown, NSW 2050. Phone (02)
519 3933.
- -
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A logic analyser and word generator make it easy to step
through a 7-segment display driver. These instruments
are brought down by clicking and dragging them from the
top screen row.
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Complex digital circuits can be simulated by the
Electronics Workbench. This circuit is a BCD decoder
which is based on simple logic gates. The right-hand
column shows the components "parts bin".
APRIL 1992
57
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