I luvv it! The STIMULATOR.

[Skogsgurra]

I only recently discovered the Linear Technology Spice simulator. It is awsome and at a great price!

Go to

http://www.linear.com/mylinear/login.jsp

register and then go to

http://www.linear.com/designtools/software/#Spice

and download the LTspice IV. "A high performance Spice III simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators"

Never again wait forever in circuit simulations where fast edges co-exist with long time constants or while the simulator tries to converge in impossible situations. Never again add resistors parallel to diodes to get a result at all.

I have gained new insights by using this simulator. I had, for instance observed that a home-brew calibrator with very fast edges produced parasitic low amplitude spikes of opposite polarity when switching a transistor off (no, no inductive kick-backs). Never understood why, but LTspice revealed the whole truth.

Switching a transistor off very quickly sometimes means "sucking" too many carriers out of the base region. And that produces a short, but noticeble, negative excursion on the collector. It is so obvious when you see it in the simulator. Changed capacitor parallel to the base resistor and transient gone!

I do not call it a simulator - STIMULATOR is a much better word for it.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[Comcokid]

It is great, once you realize it's a Spice simulator without the typical node or component limits of a freebie, and that it is an enhanced Berkley Spice at its heart that doesn't even limit itself to Linear Tech parts, it's great.

I only re-discovered it in the past few months, and am quickly trying to relearn using a Spice program. The schematic interface of the LTSpice is great. When I went to school, I had to punch the spice on IBM cards and submit the cardstack to the high priest of the mainframe.

 

[IRstuff]

OK...

I haven't needed a SPICE simulator in 21 yrs, but you guys convinced me to download it.

Have no idea what I'd do with it now, but I have it ;-)

TTFN

FAQ731-376

 

[IRstuff]

Oh, btw... the transient behavior you describe is true for diodes as well, if I remember correctly

TTFN

FAQ731-376

 

[Skogsgurra]

I think that is the Reverse Recovery Current. Is it really the same thing in a transistor?

Yes! You are right. The base-cathode diode charge carriers of course behave the same as those in the standard diode. Never too late to learn new things - or view them in a new light. Thanks!

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[zappedagain]

This is a nice tool; I've been using it for a while. We also have a purchased spice simulator here, so occasionally I'll compare them (typically when someone else has already started something in the purchased version). I typically have more faith in the LTSpice results! I've found the setup is much simpler and therefore less error-prone.

Z

 

[itsmoked]

I use it all the time. It's especially useful in that most of their complex parts come with full demo circuits that you can just download and plop into it. Then mess with values. Stuff like their switching controllers. (Switcher Spice)

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Noway2]

And who do YOU (Mr ItSmoked) have to thank for tipping you of to it eh?

I've been using it for a few years now. A couple of times it has come in really handy to prove / disprove a concept that the boss wanted to investigate.

 

[itsmoked]

Yes, yes, I bow to the Simulation King

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Noway2]

I am only giving you a hard time because of how you reacted to the idea of simulation at first.

Glad to see that you have come around. I guess we could say you are "recovering"

 

[itsmoked]

Funny you should say that, "recovering".. I spent the night on the bathroom floor and am sicker than a dog. I have had on minuscule sips of water for 24hs.. <groan> I had to take a shower.. I could not figure out how the fixture worked! I have used it every day for 10 years.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

Noway is running that o'l black magic on you Keith!

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[itsmoked]

He must have a voodoo doll that weighs 30lbs due to all the skewers. I just had to take another shower and still couldn't figure ouyt the fixture... weird.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

What hit you, Keith? Bad oysters?

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[itsmoked]

I always think it's something I've eaten as these things often hit me really fast. I was fine at 7pm at 8pm I'm a wreck. Must be something I ate. Then I note a 102F temp and that can't be food related. I'm starting to feel a little better though I haven't had more than 5 crackers since Monday.
I think it was just the local, 'season's greetings'.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[IRstuff]

Actually, it can. The usual shellfish warning concerns both viruses and toxins. Viral infections can bring on fevers.

TTFN

FAQ731-376

 

[itsmoked]

Food poisoning can cause elevated temperatures?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Noway2]

I have an uncle who got hepatitis from eating lobster. That is one nasty disease that the effects of which never really goes away. Thankfully he got the kind that is not contageous from human to human.

 

[itsmoked]

Youch!

I have looked up temperatures and food poisoning. Amazingly of the approximately 12 non-chemical common food poisonings available for selection by humans at least half include marked temperature rises with onset. Now I know.

I had an epiphany, it actually makes sense since! I have always kept FP and any other common cold/flus in separate categories. In reality they should be looked at as the same thing. They are both organic attacks by foreign organisms on the body. One is just the "low route",(GI tract), and another the "high route",(respiratory system), with, of course, various in betweens and exceptions. Of course, raised temperatures would a possibility!

To a healthy Christmas season for everyone! [santa2]

Keith Cress
kcress -

http://www.flaminsystems.com