Suggestions and things to add

Good evening,

I hope you’ll allow me to suggest some features that I wish to be in future:

  1. ddt() operator in behavioural sources (for implementation capacitor through charge formulation without using subcircuits with capacitor or inductor)
  2. Voltage/current dependant resistance with syntax “Rx n+ n- R=F(V,I)” - I know that it could be easily done with behavioural source, but for the sake of clarity ii is good to have it in simulator.

Regards, George.


OK, the behavioral resister is implemented in yesterday’s update. Both Norton and Thévenin equivalents are supported, the later in case you want zero to be a valid resistance.

The ddt(), idt(), et al. relate to another aspect I’m strategizing on and won’t be immediately available.



I would like to congratulate Quorvo team and Mike Engelhardt personally on the QSPICE beta release.
Also I want to thank Jeff Strang for help and the opportunity to download the QSPICE.

I started with QSPICE today and will collect my questions and suggestions.

  • Could you add LTspice style NMOS and PMOS symbols by default, please?
  • Also there are some mistake in SCHMITT symbols description (see screenshot, please)
  • Any information about limitation of PSPICE model support?

I have LTspice schematic with TI LM25085 (unencrypted official TI model) successfully modeled.
I redraw schematic in QSPICE and have errors. As far as I understand VSWITCH is not supported.
I replace VSWITCH with SW in model file and fix some other errors. Simulation start but results is not correct… I investigating what can cause this issue and let you know results later.

– Kindly Regards,

I’d like to see the ability to read/write a .wav file like LTspice allows. I use it when designing audio circuits so I can evaluate how it “sounds” (to some extent) before deciding to prototype it. I has worked fairly well (if you allow for the possibilities of aliasing.

I`m very pessimistic about using QSPICE ( and any SPICE) as listening tests setup:)

  1. Real components is not the same as models.
  2. Most of OPAMP models is not include distortion, PSRR

– Regards,

Suggestion: add a function to export the circuit (and waveforms) as a vector file (SVG or EMF).


There is the ability to export waveform data in equally spaced timesteps in case you want to plot it in Excel. But since the graphics are done with the GPU(DirectX12) the bitmaps are already publication quality. You can put them on the clipboard, paste them into; e.g., mspaint; and save as a .png. I don’t think any desktop publishing software does a better job rendering the vector CAD data than QSPICE.

I noticed that Mike only addressed the waveform data part of the suggestion.

Respectfully, QSPICE does need a pulldown menu feature to export the schematic to a file without requiring the user to use O/S features or screen capturing software to do it.

  • Export Schematic to PNG file as Color
  • Export Schematic to PNG file as Black
  • Export Schematic to SVG file as Color
  • Export Schematic to SVG file as Black

At a barebones minimum, sooner than later, the first two PNG features should be added to QSPICE.

In the long term, the SVG features needs to be added for professional quality results for use in printed publications / technical documents / college thesis / WORD / WRITER (LibreOffice) / …

If you really want QSPICE to be the modernized step-up in the simulation world, then you need to add new features (like this) to lock people into migrating and staying with QSPICE.



There’s right click=>Copy Bitmap to Clipboard. Paste that into your e-mail or desktop publishing software.

I use PDF for ALL files that I need for store or share.
Simply install any free PDF printer, or use standard Windows PDF printer.

What about Cadence, Mentor, Synopsys, Altium and Zuken?


  • Tools / write image to .emf file

A comparison of the image exporting abilities of various Windows software.
Hopefully other readers will report similar information for other paid software!

QSPICE (Jun 28 2023 build): (free; Windows)

  • Schematic and Waveform window:
    • File → Print → Microsoft Print to PDF → PDF file
    • Right Click → Copy Bitmap to Clipboard

LTspice v17.1.9: (free; Windows & Mac)

  • Schematic window:

    • File → Print Monochrome (checkbox setting for printing)
    • File → Print (per checkbox) → Microsoft Print to PDF → PDF file
    • Tools → Copy Bitmap to Clipboard
    • Tools → Write Image to EMF file
  • Waveform window:

    • File → Print (per checkbox on schematic window) → Microsoft Print to PDF → PDF file

Micro-Cap v12.2.0.5: (free / previously paid; Windows)

  • Schematic and Waveform window:
    • File → Printer Preview →
      • → Black and White (checkbox setting for printing)
      • → Gray Scale (checkbox setting for printing)
    • File → Print → Microsoft Print to PDF → PDF file
    • Edit → Copy to Clipboard →
      • → Copy the Visible Portion of Window in BMP format
      • → Copy the Select Box Part in BMP format
      • → Copy the Entire Circuit Page in BMP format
      • → Copy the Entire Window in WMF format
      • → Copy the Entire Window in EMF format
    • Edit → Export to Graphic File →
      • → BMP / JPG / GIF / EMF / WMF / TIF / PNG

Qucs-S v1.1.0: (free; Windows / Mac / Linux )

  • Schematic window:

    • File → Print → Microsoft Print to PDF → PDF file
    • File → Print Fit to Page → Microsoft Print to PDF → PDF file
    • File → Export as Image → (choice of Color or Monochrome) →
      • → PNG / JPG / SVG / PDF / PDF + LaTeX / EPS
  • Waveform window:

    • Right Click → Export as Image → (choice of Color or Monochrome) →
      • → PNG / JPG / SVG / PDF / PDF + LaTeX / EPS

SIMetrix/SIMPLIS Elements v8.50i: (free limited demo / paid; Windows)

  • Schematic window:

    • File → Print (has Monochrome checkbox option) → Microsoft Print to PDF → PDF file
    • File → Save as PDF
    • File → Save Picture →
      • → Bitmap (default image size): PNG / JPG / BMP
      • → Bitmap (specify image size): PNG / JPG / BMP
      • → Windows Meta: EMF / WMF
      • → Scalable Vector Graphics: SVG
  • Waveform window:

    • Right Click → Copy to Clipboard → Color / Monochrome / Color with Markers

Circuit Lab (July 1, 2023): (paid; Website) (example CircuitLab - Editing “Unnamed Circuit” )

  • Schematic window:

    • File → Print/Export PDF
    • File → Export PNG / EPS / SVG / SVGZ
  • Waveform window:

    • Right Click → Save Image As (using web browser feature)

Software lists:

Raster bitmap image file formats:

Vector image file formats:

Windows meta image file formats:

Document file formats:


Please don’t flood the forum with unnecessary information.
All of us know about Wikipedia. This forum is not for discussion about graphic formats.

– Regards,

I would too appreciate a possibility to export both schematics and waveforms into vector format . Ideally .svg but .emf would do as well (as in LTSpice). I don’t need to explain the advantages of vector format, but my particular use case is, that as system engineer, I often import it to MS Visio and do some post processing on it.

Thanks @Engelhardt for considering this.

Kind regards,
Tomas Urban

1 Like

Since QSPICE is using the GPU to render the schematics and waveforms, there’s little to gain with vector graphic export. It already looks better than most software can render vector graphics, well, you know, unless you’re working on a 600x800 screen resolution and are preparing documentation for someone who wants to view your image full screen on 4K.


KiCad (with integrated ngspice) seems to be missing above:

One thing is not needing to care about actual resolution. Especially with large screen you have many smaller windows on it. If you export multiple waveforms/schematics in different times on different screens you need to watch they are same resolution/size. If you don’t the line thickness is different, symbols are different etc.

Another thing i mentioned in my comment is editing: Vector format is editable way better (changing colors, thicknesses, fonts etc) in variety of SW tools. You can’t do that with bitmap (at least not with reasonable effort and repeatability)

I understand this is not on top of priority list, but i’m convinced it would be valued by many engineers.


I have personally been caught out by this when producing academic publications with other software. It is painful to have to go back and try and get consistent scaling to generate a professional output. Also, software such as Latex really prefers vector graphics. Publication quality != easy to work with for publishing.

I’m all for fast rendering and excellent on screen graphics. But the option to export a vector format via a menu - or from the .qsch file via a post processor - would be wonderful.

Thanks for an excellent product!


@GeoffW ,

This discussion has gotten me curious.

The Export option in the Waveform viewer tends to be a .csv file of requested data points with a time of occurrence.

By it’s very nature, it is a form on PWL output. The PWL format is a vector format. Maybe not a a specific vector format you are looking for.

I imagine on the web there are programs out there that will take .csv format and convert it to your specific vector format.

I regularly use Excel to import my .csv files and use the data points to create a vectored graph.

If you’re taking about exporting a bitmap, you are correct. This is not vector formatted.