LT Spice Question

You *can* use the standard voltage source, making the voltage a curly-brace function of a parameter, which you can define externally, and step.

Like:

Version 4 SHEET 1 880 680 WIRE 336 80 96 80 WIRE 96 112 96 80 WIRE 336 112 336 80 WIRE 96 240 96 192 WIRE 208 240 96 240 WIRE 336 240 336 192 WIRE 336 240 208 240 FLAG 208 240 0 SYMBOL voltage 96 96 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value {1+ .001*(temp-tamb)} SYMBOL res 320 96 R0 SYMATTR InstName R1 SYMATTR Value 1 TEXT 96 304 Left 0 !.op TEXT 96 288 Left 0 !.step temp 0 50 10 TEXT 96 272 Left 0 !.param tamb=20

There's your 1 volt source (at ambient), with a +1mV/degree C TC, using the Spice builtin temp variable, which should be global for all devices that support TC.

No need for BV. Adapt to whatever you want.

My (early) xchm won't go beyond the first page of "modern" CHM. I guess M$ "improved" the format.

Later versions need library updates I'm reluctant to do, since every time I do, something else breaks.

This system is stable. Does everything I want. I'd like to keep it that way.

Excellent. Thanks.

John

I asked a question about something I didn't understand, and got useful answers. Engineering isn't about personalities, it's about facts. Being an old hen is all about personality.

The other interesting thing about hens is that they are chicken.

John

On a sunny day (Thu, 04 Nov 2010 07:20:20 -0700) it happened John Larkin wrote in :

I agree with you. I did not know the temp thing in LT spice either, so I saved those postings, in case I ever need it. For the rest I am not interested in the fascist racist and other dumb ideas of J.T. & Co. maybe the inroads they made in this election went to their heads. In my personal view it changed the US back to a lame duck. I watched some youtube video of Boenher (?spelling) yesterday because I wanted to see what sort of frame of mind he had. According to him well, he does clearly not know a lot about chemistry.

Oh maybe not, would be the same everywhere anyways, Oops ? Drifting of subject.

case I ever need it.

What would be cool would be one huge LT Spice schematic with lots of special cases included: ideal diodes, temperature things, a really good ideal opamp, parameter sweeps, nonlinear gadgets, stuff that's tricky to figure out from the HELP system.

Somebody with time could manage that, and accept contributions.

J.T. & Co.

The US populace is basically conservative. Obamamania was an exception, a moment of madness.

Most of the european countries are moving to fisical conservatism, and I hope the US will, too. You can't spend your way to prosperity, or to happiness.

In the long term, ordinary US voting citizens, the "great unwashed mass" as the lefty snobs call them, have more collective wisdom than a barn full of Harvard economists.

John

OK, it appears my xchm is currently 1.17

But I've been using whatever has been in debian sid for the past 5 years or so with no problems. It wasn't a big deal to install, just the usual

aptitude install xchm

It remembers the last few files viewed so you don't have to go looking for the help file location each time.

Larkin seems have missed the fundamentals... act like an asshole... reap the benefits ;-) ...Jim Thompson

Have you looked at /examples/Educational?

Xchm here is 0.9.3, compiled from source, like most of what I use. This isn't really a distro, it started life in 1999, and has been lovingly handcrafted over the years to be just what I want. Most things have been compiled from source, hence my reluctance to start another dependencies chase. This system is on its second machine and umpteenth HDD, just dd'd over, and hand tweaked for hardware changes.

On a sunny day (Fri, 05 Nov 2010 11:40:33 -0700) it happened Fred Abse wrote in :

There is an other solution, for example in my fight to get the latest firefox running, I tried a chroot.

I just got the latest copy of grml

I installed the latest distro on the /dev/hda4 partition # mount the latest grml mount /dev/hda4 /mnt/hda4

# use DMA hdparm -d 1 /dev/hda

This trick seems to be needed to get audio working # for audio mount --bind /dev /mnt/hda4/dev

# do a chroot chroot /mnt/hda4

I created a user 'test' for this: # login as user test [ password ....] ##login -f test

The 'display' variable is needed # start firefox ##./firefox --display 0:0

# after exit (twice): # umount /mnt/hda4/dev

All this in one rxvt..

It is slower than normal, but it works. Wrote a script for it, but have not used it since though:-)

Cool, and it runs wine OK? Anyway, the PDF version is the same as the chm IIRC, so you can just use xpdf (or the reader of your choice).

Yes. What we could do is all the stuff that's not there.

Incidentally, why don't the standard ideal opamps work right out of the box? I wind up using VCVSs instead.

John

They need a level specifying, see /examples/Educational/UniversalOpamp2.asc

VCVS's don't behave like an OpAmp... even ideal OpAmps exhibit 90° phase shift over most of their useful range.

I know that Mike Earnhardt has one like this...

that allows setting GBW, DC-gain, slew-rate, excess-phase, etc.

Then some of us create our own gadgets for testing with simulation, like current-limited power supplies, current sources with limited compliance (no infinite volts :-), etc. ...Jim Thompson

Thanks.

Yup.

It seems that all "Helps" assume you already know what you are doing.

Up until yesterday I used LTspice only to view schematics posted by others.

Then an old client asked how to open my .CIR and .NET files in LTspice.

It took me about six hours total... mostly in simulation time (a crystal oscillator) to sort out what LTspice likes and dislikes.

Mostly just some trivial text editing.

However it'll take a while to figure out how to get my specialty tools into LTspice.

One major hiccup, off-the-bat, LTspice won't do "avgx" (average over an interval) in their post-processor. ...Jim Thompson

The best it has is the thing in the waveform display. Not the same.

Maybe it can be done with a .meas

I've been playing with simulating xtals, too. Using a small series resistor and a vector voltmeter looks like it might work to measure current *and* resonance, but I'm away from the lab.

Or I might even dig out a Q-meter. Have to watch the voltage, though.