Which free simulator software for mixed circuits ? (windows)

Thread Starter


Joined Mar 30, 2019
I'm a beginner at this.
I have a few simple mixed circuits that I cannot made head nor tail of and I want to simulate.

I've got QUCS but it doesn't seem to be able to simulate mixed ccts. The digital simulation complains about the diodes. The transient simulation creates a netlist but then chokes. It probably could be made to work if you know what you are doing.

I have looked at a few of the online options but they either wont do mixed ccts or have very limited libraries and don't offer the components I need. Some where in the back of my brain I seem to recall that everything in the TTL data book can be implemented using only nands, but that is too much faffing around. Some progs just wouldn't load at all or maybe they were so slow that I gave up.

So as the title says, as a beginner, which software should In be looking at?


Joined Mar 14, 2008
Several of us on this site use the free LTspice simulator from Analog Devices (formerly Linear Technology).
It's one of the best free analog simulators available.
It has a somewhat steep learning curve, but many simulation examples are included along with a fairly helpful tutorial.
It doesn't come with digital models, but model libraries for many of the CD4000 and 74HC devices are available from the Yahoo user's group.

Thread Starter


Joined Mar 30, 2019
Hi Scott, I did see your thread.

At the time I read it I wasn't sure if LTspice would simulate circuits with both analog and digital components.
And if it did, how beginner friendly it is so that I can work out how to do it.

My very cursory look at it suggests it is going to take a while to get used to. (ie to 'unlearn' what I'm used to doing).
My simulation keeps failing with "step size too small". However , as I said, I have not really looked at it yet.


Joined Aug 23, 2012
Many our old members they used that software quite well, like @crutschow, @Bordodynov and some others, so when you meet any problems, you just upload the *.asc file then they can help you, please click the button "Upload a File" at the bottom line to upload your *.asc file.

Good Luck.