From: Andy Fierman <andyfierman@si...>  20140604 12:11:10

Denis, You may need to take a little time to get out of the "Simplorer way" of doing simulations and try to think at a lower level. Simplorer gives you ready made blocks to do things but QUCS (in the same way as spice simulators) gives you basic components and equationdefined devices or EDD a.k.a. (behavioural, arbitrary or dependent sources in spice) from which you can build more complex functional blocks. You do not need to build a PWM block out of transistors in QUCS: you can do it using something like a Voltage Pulse Source set to generate a sawtooth or a triangle wave and then use an EDD to define a comparator function with a bounded output swing (I'm not too familiar with the QUCS EDD but in spice it would be something like Vout=0.5*Vswing*(tanh((V(in1)V(in2)*Avol)+1) where Vswing is the 0V to max output voltage swing and Avol is a notional open loop gain, usually around 1k is OK here). You'll find these bits here: Components > sources > Voltage Pulse Source Components > nonlinear components > Equation Defined Device There are of course many more parts under the Components tab ... :) For info on EDD see: "Introduction to equation deﬁned devices (EDD)" starting p24 in: http://qucs.sourceforge.net/docs/tutorial/equations.pdf Although I probably shouldn't say it here you might also like to look at: Scilab and the Xcos toolbox: http://www.scilab.org/content/download/1107/10095/file/Xcos_beginners.pdf and: Scicos: http://www.scicos.org/ Cheers, Andy. signality.co.uk On 4 June 2014 12:09, Frans Schreuder <fransschreuder@...> wrote: > Dear Denis Rakar, > > We can surely help you, but I don't know how  your question is missing > some essential information. > you should be able to use a rectangle voltage source, but you say it > doesn't work. Can you say what doesn't work? > > Frans > > On 06/04/2014 12:51 PM, denis rakar wrote: > > hi, > > > > I am a student of electrical engineering in Croatia. and have to simulate > > an DCAC converter for an project. we usually use a Simplorer 7 student > > version, but there I can't simulate more then 15 elements. So i has found > > your software QUCS version 0.0.15. but I can't simulate an ordinary dcdc > > converter, i think because it hasn't an PMW modulator. I tried use an > > rectangle voltage source, but it doesn't work. Please can You help me? > > > > Best Regards. > > > > Denis Rakar, > > Student of electrical engineering, at the Technical University of Rijeka, > > Croatia > > >  > > Learn Graph Databases  Download FREE O'Reilly Book > > "Graph Databases" is the definitive new guide to graph databases and > their > > applications. Written by three acclaimed leaders in the field, > > this first edition is now available. Download your free book today! > > http://p.sf.net/sfu/NeoTech > > _______________________________________________ > > Qucshelp mailing list > > Qucshelp@... > > https://lists.sourceforge.net/lists/listinfo/qucshelp > > > >  > Learn Graph Databases  Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and their > applications. Written by three acclaimed leaders in the field, > this first edition is now available. Download your free book today! > http://p.sf.net/sfu/NeoTech > _______________________________________________ > Qucshelp mailing list > Qucshelp@... > https://lists.sourceforge.net/lists/listinfo/qucshelp > 