Re: gEDA-user: perspective on marketing vs. substance

[al davis <ad151@xxxxxxxxxxxxxxxx>]

On Friday 07 September 2007, John Griessen wrote:
> I just saw a couple of posts that seem to confirm
> that it is behind PCB in capability, but very appealing to a
> newbie,

A similar situation exists with "Multisim".  Using it is like 
playing a video game, but it is a real challenge to do serious 
work with it.

I recall when I was teaching .. Part of a homework assignment 
was to verify the DC operating point of a circuit, using 
simulation.  I wanted all node voltages, collector currents, 
etc.

With gnucap, you do "print op v(nodes) I(q*)" then "op".  With 
Spice as it comes from Berkeley it is easy, too.

One of the students, using Multisim, handed in a stack of about 
20 plots, with each of the values against time.  Of course, 
they were all straight lines.  Each one .. attach the scope 
probe, turn it on to see the waveform, screen capture ......

Multisim is just Spice made to look pretty.

Too often, teachers cover only the GUI.  The students never see 
a netlist.  Then they are clueless when something is a little 
strange.  Students put "PSpice" or something like that on the 
resume, because they are told that is the most popular.

Later on, another project was a class-B audio amplifier.  Check 
out the AC analysis ....  Of all the simulators available, only 
gnucap was able to do a correct AC simulation.  Only gnucap had 
the features needed to adjust the bias easily, the way you do 
on the bench.  (Turn up the current until the crossover notch 
disappears.)


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