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By ROBERT PENFOLD

Robert puts some circuit simulation and analysis

software through its paces.Robert puts some circuit

Edison 3 is a relatively new

and little known program in the

UK, but it is a piece of software

that is likely to produce a great

deal of interest amongst those

who teach electronics. It is for

PCs only, and requires a mini-

mum of a 80486 CPU, 8MB of

RAM, 10MB of hard disk space,

VGA graphics, and Windows 95

or higher. The

recommended

minimum system includes a

Pentium class processor, a 16-

bit graphics card, and a

SoundBlaster or compatible

sound card.

The software is supplied on

a CDR disc, and a CD-ROM

drive is therefore required as

well. It is a definite plus point

that Edison 3 will work quite well

on older PCs, but a Pentium PC

with a good graphics system is

needed in order to get the most

from it.

Installation is reasonably

straightforward and follows

along normal Windows lines.

There is a separate booklet that

covers installation and registra-

tion, and replaces the initial sec-

tion of the main manual. The

program originally used a hard-

ware “dongle” fitted to a printer

port, but this has now been

abandoned in favour of a “key”

number that is obtained by reg-

istering the software.

Without the “key” number

the program will operate for 15

sessions, which

should give suf-

(',621 5(9,(:

ficient time to register and ob-

tain a reply. This all seems like

an unnecessary complication,

but it is much better than deal-

ing with troublesome “dongles”.

SPLIT PERSONALITY

So just what does Edison 3

actually do? It is a form of cir-

cuit simulator, but one that is

tailored to suit the teaching of

electronics. It has obvious simi-

larities to the popular

Crocodile

Clips

program that was re-

viewed in a previous issue of

EPE,

and circuits can be built

up and tested on what is best

described as a virtual bread-

board.

The virtual LEDs light up

and switch off in the appropriate

fashion when a circuit is tested,

and the virtual loudspeaker will

even produce the appropriate

sounds via the PCs sound sys-

tem. Resistors are given the

correct color code automati-

cally, or they can be labeled

with their values if preferred.

Fig.1. Edison 3 operates using a split screen

with the breadboard on the left and the

schematic analyzer on the right. Components

are dragged onto the breadboard and wired

up, automatically producing the circuit dia-

gram in the process.

Maxfield & Montrose Interactive Inc

Fig.2. The graphs on the virtual test instru-

ments are quite small, but they can be shown

in a resizable window. This window permits

some basic editing of the graphs, and also

provides printing and export facilities.

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6SHFLDO 5HYLHZ

Overloaded components go up

in smoke and have to be re-

paired.

The 3D graphics are quite

good, although I found it a bit

difficult to identify some of the

components when first using the

system. Sound effects are avail-

able if required.

When the program is run, it

operates with a split screen hav-

ing the virtual breadboard on

the left and a schematic editor

on the right (Fig.1). Both Win-

dows are resizable, and either

can therefore fill the screen if

required. Circuits are built up on

the breadboard, and the corre-

sponding circuit diagram is pro-

duced automatically in the

schematic editor.

The breadboard window has

two “shelves” of components in

the top left hand and bottom

right hand corners, and clicking

the mouse on the background of

either cycles

the program

through a num-

ber of addi-

tional

“shelves”. The

components

are simply dragged onto the

breadboard area and then wired

together with trails of virtual

wire using the mouse.

It is easy to delete wires

and components, and compo-

nents can be dragged to new

positions if desired. However,

any wires attached to compo-

nents are automatically deleted

if the components are moved,

so it is advisable to get the

components arranged neatly

before adding any wiring. It is

also advisable to look at the

schematic editor while placing

components, to make sure that

a reasonably neat layout is pro-

duced in both windows.

COMPONENT

RANGE

The range of

components avail-

Fig.3 (above). The stan-

dalone schematic ana-

lyzer loses the virtual

breadboard front-end

and the separate control

panel, but gains more

conventional component

toolbars. The tabs give access to ten sets of

components, and these provide a much wider

choice than is possible using the virtual bread-

board. This screen also shows how notes can

be added to circuits.

Fig.4 (above right). Right-clicking on a component and then se-

lecting “Properties” brings up a dialog box (bottom right) that en-

ables the value and characteristics of a component to be al-

tered. The virtual test instruments, like the signal analyzer

shown, are available in the standalone schematic editor.

Fig.5 (right). All the analyzing facilities remain available in the

schematic editor. These graphs show the phase and frequency

responses of an ill-conceived lowpass filter. The sensible scal-

ing makes the graphs easy to interpret.

Maxfield & Montrose Interactive Inc

able is quite limited, but it in-

cludes all the basic components

such as resistors, capacitors,

and a pushbutton switch. There

is a small but useful range of

semiconductors available, in-

cluding various types of transis-

tor, a 555 timer, 741C opera-

tional amplifier, and some sim-

ple flip/flops. This section of the

program is not usable as a

general-purpose circuit simula-

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6SHFLDO 5HYLHZ

tor, because the range of avail-

able components is too limited,

but it should be possible to test

a wide range of simple begin-

ners’ projects.

Some of the components

provided are actually test instru-

ments, such as power supplies,

various types of meter, a signal

generator, an oscilloscope, and

a signal analyzer. The latter is

used to produce such things as

phase and frequency response

charts.

With the aid of the test in-

struments it is possible to show

how well (or otherwise) the test

circuits perform, in addition to

undertaking fault-finding

checks. You can test compo-

nents, measure voltages, etc.,

so that the virtual fault can be

traced in much the same way as

when testing the real thing.

The test results produced

on the screens of the signal an-

alyzer and oscilloscope are diffi-

cult to see due to their small

size, especially when using a

high-resolution screen. It is an

easy matter to display results in

a separate window though

(Fig.2), and this shows them

very clearly with sensible label-

ing. There is no unnecessary

use of scientific notation or la-

beling at odd intervals such as

every 21 35Hz! The charts can

be printed via the system printer

and they can also be exported

as Windows metafiles or

bitmaps.

spond to the average signal

voltage.

The next option is the single

transient mode. Operating the

start/stop button in the control

panel or any switch on the

breadboard triggers this mode.

The simulation then starts and

continues for a time set via the

control panel. This time can be

varied from 1

s to 10s, which is

adequate for most purposes, but

clearly prevents very brief or

high frequency events from be-

ing simulated.

Where appropriate, the sim-

ulations are slowed down to a

rate that enables the action to

be observed properly, and each

run normally takes a second or

two. This mode is useful for

capturing events such as a ca-

pacitor charging via a resistor,

or an oscillator starting up. The

third mode is a repetitive ver-

sion of the transient mode,

where the program effectively

re-triggers itself at the end of

each run. It carries on from

where it left off rather than start-

ing each simulation “from

scratch”, giving a form of con-

tinuous simulation.

mulae used to produce test re-

sults. A useful range of example

circuits are included with the

software, and these cover topics

such as Ohms law, simple fil-

ters, voltage dividers, and sim-

ple logic circuits. Some addi-

tional source material may be

required, but the package in-

cludes sufficient to get you

started and well under way.

ADDED BONUS

A program such as Edison 3

provides an excellent means of

learning about electronics, but it

can only teach you the funda-

mentals. The relatively small

number of components that are

catered for and the limitations of

the breadboard mean that many

users will soon outgrow the sys-

tem.

Edison 3 provides a solution

to this problem in the form of an

additional program that is a

more conventional circuit simu-

lator. This is effectively the Edi-

son 3 Schematic Editor, but cir-

cuits are drawn up by adding

circuit symbols directly onto the

drawing area, and a much

greater range of components is

available. Using this program it

is possible to simulate a wider

range of circuits, and much

more complex circuits are easily

accommodated.

The schematic editor is a

fairly conventional Windows

style program having the usual

menu bar, tool bars, scrollbars,

etc. Below the main toolbar

there is a selection of circuit

symbols, and below this there

are tabs that are used to select

the required type of component

(basics, gates, etc.). These re-

place the “shelves” of the Edi-

son 3 program, and provide ac-

cess to a wider range of compo-

nents. The range is still much

smaller than that available with

QUICK AND EASY

Using Edison 3 is generally

quite simple and straightfor-

ward, which is clearly essential

for a piece of software that is

intended for beginners. Building

and testing circuits using this

software is quick and easy, and

it gives newcomers a flavor of

the real thing. Integrating the

virtual breadboard with a

schematic editor should make it

much easier for students to

learn the basics of circuit dia-

grams.

The program has some use-

ful extras, such as the ability to

add notes to circuits, and in

some cases it can show the for-

IN CONTROL

Circuit analysis is controlled

via a third window, appropriately

called the

Control Panel.

This

offers three modes which are

selected via on-screen buttons.

The default mode is AC/DC,

which works with either fixed

DC levels or sinusoidal AC sig-

nals. Motors, LEDs, etc. re-

Maxfield & Montrose Interactive Inc

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6SHFLDO 5HYLHZ

Fig.6. Two traces can be included in a single

graph if desired, with a different color being

used for each one. This example shows two

output waveforms from a Colpitts oscillator.

The graph editing, export, and printing

facilities are the same as those

of the main program.

up-market simulators, but it is

sufficient to produce a huge va-

riety of circuits.

There are 18 sample cir-

cuits available and it is worth

experimenting with these to fa-

miliarize yourself with the pro-

gram (Fig.3), but it is very easy

to draw up your own designs.

This is just a matter of dragging

components into the drawing

area, positioning them, making

any necessary value changes

(Fig.4), and wiring them up.

The schematic editor has

the usual editing facilities and it

is not difficult to produce neat

diagrams that can be printed out

if required. Some schematic ed-

itors are a trifle cumbersome in

use, but this one seems to be

very straightforward. Circuits

are restricted to a single page,

but it should still be possible to

handle some quite complex de-

signs. No node limit is specified

for the analyzer, but on test it

handled some multi-pole filters

without problems.

Fig.7. Edison 3 has some digital analysis and

mixed-mode capability. Here the graphics

window effectively acts as a simple logic ana-

lyzer and shows the output waveforms from

four test points in a half-adder circuit.

analyzer style display (Fig.7).

In order to fully utilize the

circuit analyzer it is necessary

to resort to control via the

menu, but a lot of useful tests

can be carried out using the

more simple facilities available

from the toolbar. The analyzer

does not rival high-end circuit

analyzer programs as it only

provides basic phase, frequency

response, and voltage testing.

There is no distortion analysis

for example. On the other hand,

it does have analog and digital

circuit analysis, plus some

mixed mode capability.

The A5 size manual only

has about 40 pages, but it cov-

ers the basics of using the soft-

ware quite well. Even though

the program has quite a wide

range of facilities, it is so easy

to use that an outsize manual is

not really necessary. Running

through the example circuits

following the notes in the man-

ual should soon familiarize new

users with the program. The

printed manual is backed up by

the usual on-line Windows help

system.

The ana-

lyzer can be

controlled by way of conven-

tional menus and dialogue

boxes, or the toolbar includes

an equivalent of the control

panel in the main program. The

schematic editor has the same

test instruments as the main

program, and these can be used

to produce some neat graphics.

Where two traces are pro-

duced they can be shown sepa-

rately (Fig.5) or together (Fig.6).

The graphics can be saved, ex-

ported, and printed out, and this

is a strong aspect of both pro-

grams.

DIGITAL MODE

There is a digital mode so

that you can see the logic states

change at each pin of digital de-

vices, see the numbers pro-

duced on seven-segment dis-

plays, and this type of thing.

Free-running and step-by-step

modes are available. The logic

levels at test points can be

monitored and shown on a logic

Maxfield & Montrose Interactive Inc

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6SHFLDO 5HYLHZ

TEST RESULTS

Edison 3 provides a fun in-

troduction to electronics via the

breadboard front-end, and it is

about as easy to use as a pro-

gram of this type could be. A

wide range of circuits can be

handled including simple logic

types. It is capable of producing

some excellent graphs, which

can be printed out or exported

to DTP programs, etc. if re-

quired.

Edison 3 is in direct compe-

tition with an established pro-

gram in the form of

Crocodile

Clips,

and it is at a somewhat

higher price. This strategy

would normally be doomed to

failure, but Edison 3 has advan-

tages over

Crocodile Clips.

Not

the least of these is the ability to

abandon the breadboard front-

end and use the schematic edi-

tor on its own.

Using a virtual approach to

producing circuits has obvious

appeal to new users, and can

make the system much more

interesting to use as well as

making things easier for begin-

ners. The drawback is that it is

not practical to produce any-

thing more than some quite sim-

ple circuits. Using the stand-

alone version of the schematic

editor removes this limitation,

and should ensure that it takes

much longer for users to out-

grow the system.

Edison 3 is compatible with

the more advanced TINA circuit

analysis program, which pro-

vides an upgrade path if one

should be needed.

(We hope to

review TINA soon

Ed.)

This program is clearly

aimed at education establish-

ments where electronics is

taught, and it is just about ideal

for this role. It is not particularly

expensive by educational soft-

ware standards, and when one

considers the range of facilities

it provides, Edison 3 certainly

represents superb value for

money. It will also be of interest

to home users wishing to learn

the fundamentals of electronics.

ONGOING

Having used the virtual

breadboard to learn about elec-

tronics there is no need to dis-

card the program. It can still be

used as a conventional circuit

simulator when designing pro-

jects or modifying existing de-

signs. If only this type of thing

had been available when I

started learning about electron-

ics!

Edison 3 costs 99.88 UK

Pounds including VAT and

postage and is available from

Quickroute Systems Ltd., Re-

gent House, Heaton Lane,

Stockport, SK4 1BS, UK (Tel:

+44 (0) 1614-760202, Fax: +44

(0) 1614-760505. Web:

www.quickroute.co.uk).

Maxfield & Montrose Interactive Inc

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