Spice simulation

[wahab]

Originally Posted by tvrgeek

Trying to figure out SIMetrix. Of course the very first circuit I want to look at has some older transistors not in their library. I have a text string Fairchild is nice enough to supply ( 2N5551) The 388 pages of the users manual does not help me know how to get this part into the program. Could anyone offer some suggestions?

Make a folder for new models inside wich you put generaly
a text containing the parameters , then :

Simetrix --> File ---- Model library ---> Add/remove library.

Symetrix will open a browsing window ,go to your new folder and double click,
simetrix then display the new files , click on the folder name and then on "add".

[keantoken]

Originally Posted by tvrgeek

Trying to figure out SIMetrix. Of course the very first circuit I want to look at has some older transistors not in their library. I have a text string Fairchild is nice enough to supply ( 2N5551) The 388 pages of the users manual does not help me know how to get this part into the program. Could anyone offer some suggestions?

Here, most models are not very good, use these from Cordell:

CordellAudio.com - SPICE Models

You can contact me as I may have better models of popular transistors that aren't in that list.

[Bob Cordell]

Originally Posted by tvrgeek

Trying to figure out SIMetrix. Of course the very first circuit I want to look at has some older transistors not in their library. I have a text string Fairchild is nice enough to supply ( 2N5551) The 388 pages of the users manual does not help me know how to get this part into the program. Could anyone offer some suggestions?

If it helps, I have a SPICE model of the 2N5551 on my web site that I developed while I was writing my book "Designing Audio Power Amplifiers". See CordellAudio.com - Home.

Cheers,
Bob

[tvrgeek]

Originally Posted by Bob Cordell

If it helps, I have a SPICE model of the 2N5551 on my web site that I developed while I was writing my book "Designing Audio Power Amplifiers". See CordellAudio.com - Home.

Cheers,
Bob

Much thanks Bob. I am working my way through your book to learn a bit about amps. Amps just plain got me intrigued. They are a lot more subtle than they look. The problem is that books don't answer questions.

I would guess you have the 5401 as well as you used that in the book. I am playing with an old Hafler DH-120 as a learning experience. The way it is built, it is hard to probe, so learning Spice seemed reasonable.

[Bob Cordell]

Originally Posted by tvrgeek

Much thanks Bob. I am working my way through your book to learn a bit about amps. Amps just plain got me intrigued. They are a lot more subtle than they look. The problem is that books don't answer questions.

I would guess you have the 5401 as well as you used that in the book. I am playing with an old Hafler DH-120 as a learning experience. The way it is built, it is hard to probe, so learning Spice seemed reasonable.

BTW, if you are not using LTspice, I urge you to try it. It is free and in my opinion maybe the best. I use nothing else. Everything in my book was done with LTspice, and my two chapters on SPICE simulation are LTspice-centric and can help one learn LTspice. There is also info on my web site about downloading and getting started with LTspice, and also ready-to-run LTspice amplifier simulations. You can literally be LTspice'ing in ten minutes.

Best,
Bob

[tvrgeek]

COOL. Worked like a charm.

[tvrgeek]

Quick update. I had to make a couple small edits on Bob's models to run in Simetrix. No "mfg" tag for example. I also dug out the Exicon models. I am pretty much getting a hang of it. The function that I can't get use of is the pole zero function. It spits out a list of complex numbers and sort of says, have a ball. It would be very nice if one of these tools actually provided Bode plots. I may try to move up to LTSpice eventually now I have a little clue what I am looking for. I have a few more functions to try.

[keantoken]

At the beginning, the quality of your simulations will depend more on your tenacity and attention to detail, than the simulator used. You should verify your models and see in what areas they aren't realistic. Otherwise, you will not know what you're missing. Even Cordell's models don't model quasi-saturation, so transistors will behave overly nice at low Vce.

[tvrgeek]

I figure sim on one end, breadboard on the other. I see sim as a tool to get me to the breadboard sooner.

Any hints on P-Z analysis?

[keantoken]

I don't know about P-Z analysis, I don't even know what it is, but in LTSpice I just use the AC analysis to see bode plots. LTSpice also has Cartesian and Nyquist mode (I understand Bode and Cartesian, but Nyquist is still quite mysterious to me). But surely Simetrix has an AC analysis or bode plotting function.