Re: shunt trouble

Jacques.Le-Coupanec <at> ac-rennes.Fr <Jacques.Le-Coupanec <at>
ac-rennes.Fr> writes:

> 
> Hello and Season's greetings
> 
> I tested it on different versions with cygwin on XP. One of them was  
> gnucap-2009-11-10.
> It seems that gnucap doesn't simulate the whole circuit when I connect 
> two logic gates with
> a null voltage source in order to get sel=out1.
> 
> It was a big circuit but I took away all the gates that were not 
> relevant to show what seems a
> bug. So I have just now out2 = AND(sel, NOT(sel)) with sel = out1, out1 
> = AND(in,in) and in = 0
> 
> out2 is not as expected : AND(sel=0, notsel=5) = 5 !
> 
> Here the Gnucap file
> GnuCap File : circuit description
> Vttl TTL 0 5
> Vin in 0 0
> UAND1 out1 0 TTL TTL in in cmos and
> Vshunt sel out1 0
> UINV notsel 0 TTL TTL sel cmos inv
> UAND2 out2 0 TTL TTL notsel sel cmos and
> .model cmos LOGIC (vmax=5)
> .print tran + V(in)
> .print tran + V(out1)
> .print tran + V(sel)
> .print tran + V(notsel)
> .print tran + V(out2)
> 
> And the result for tran analysis:
> 
> #Time       V(in)      V(out1)    V(sel)     V(notsel)  V(out2)
>   0.             0.           0.            0.            5.             5.
>   100.E-6   0.           0.            0.            5.             5.
> 
> If I don't use Vshunt it works but what's the matter ?
> 
> And Al, thanks for all the job you have done.

gspiceui, with ngspice, and gnucap or ngspice, and gnucap stand alone. The
applications have simulation problems where semiconductor devices parameters
aren't defined properly. I have been successful at simulating devices with
only capacitors inductors and resistors. I have also not been able to find
any references of libraries containing semiconductor devices parameters
useful to bypass the simulation problems. I did find one article and have
since lost track of it that mentions parameters within the semiconductors'
netlist must be removed in order to get simulation results. gnucap simply
displays: #nucap         0.35 and ngspice simply displays messages where it
asks; "What is this?". These errors occur while using "QUCS". The linux
application "Electric" is what gave me the proof of problems occurring with
 gspiceui, with ngspice, and gnucap or ngspice, and gnucap stand alone. I
simulated a device using only capacitors inductors and resistors, and as I
placed a single diode within the device, it ceased simulation with the above
mentioned results.