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felipeduque

Member

Registered: 2015-03-02

Posts: 16

Netlist converter: Qucs to spice

Intended for electrical engineers students/professionals/enthusiasts:

I use both Qucs and ngspice a lot. Qucs' GUI is very easy to use and ngspice is extremely powerful. However, ngspice doesn't have a GUI by default, so I thought of a way to combine Qucs interface with ngspice functionality. I think gEDA schem exports spice netlist; however, I personally don't like its feel - I use it only for manufacturing pcb.

The script

qucs2ng input output

converts Qucs netlist (located in ~/.qucs) to a spice netlist by simply using a bunch of sed instances.

Example:

The following Qucs circuit generates the ~/.qucs/netlist.txt below:

# Qucs 0.0.18  /home/felipe/test/test.sch

R:R2 _net1 vo R="10k" Temp="26.85" Tc1="0.0" Tc2="0.0" Tnom="26.85"
R:R1 _net0 vo R="20k" Temp="26.85" Tc1="0.0" Tc2="0.0" Tnom="26.85"
Vac:V1 _net1 _net0 U="3" f="100k" Phase="0" Theta="0"

After running

qucs2ng ~/.qucs/netlist.txt test.cir

we have the following proper spice netlist:

# Qucs 0.0.18  /home/felipe/test/test.sch

.include /home/felipe/.spicemodels
R2 1 vo 10k
R1 99 vo 20k
V1 1 99 SIN(0 3 100k)

.end

How to use

1. Design your circuit in Qucs.

2. Make sure all your elements values are in accordance with spice syntax. For example: '10 Ohm' should be just '10'; '5 MHz' should be '5Meg'.

3. Run a Qucs simulation by hitting F2.

4. Run the script:

   qucs2ng ~/.qucs/netlist.txt myspice.cir

   .

5. If you have written a .control script in myspice.cir and want to keep it after changing the schematics, run

   qucs2ng -a ~/.qucs/netlist.txt myspice.cir

   .

Notes:

1. The current script can handle BJT (npn, pnp), op amp, DC/AC/pulse source, diode, capacitor, resistor and inductor.

2. Change your spice models file in line 136.

Download here:

https://sites.google.com/site/duquebelf … para-spice

Last edited by felipeduque (2015-03-13 00:09:57)

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,334

Re: Netlist converter: Qucs to spice

Pretty good.  Are your sources capable of sweeps? Or are these AC and DC operating point only at this point?   Obviously one can edit the script, but.....

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felipeduque

Member

Registered: 2015-03-02

Posts: 16

Re: Netlist converter: Qucs to spice

Hi,

the script doesn't handle .control blocks (where sweeps would take place). It simply builds the circuit in a spice format. You can do whatever you want with the sources in a .control block