LT Spice Question

C:\Program Files\LTC\SwCADIII\lib\cmp\standard.dio

I believe

-Lasse

/lib/cmp/standard.dio

Use a standard editor and add/edit what you want.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

OK, thanks.

Next question: how can I create a voltage source with a known temperature coefficient? There's no LM134 model. I've tried using variable name TEMP in voltage source expressions, but it doesn't recognize the symbol.

LT Spice HELP isn't great.

John

There's a Yahoo group for it:

I guess you'll have to roll your own behavioral source.

Help never is, IME. It's worth getting the PDF manual from LT. Nothing that isn't in the online help (AFAIK, the online help doesn't work under wine), but it's easily printable. Useful as desk reference when cooking behavioral stuff.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

I've tried to register half a dozen times, and it's always come up with some (untrue) reason not to let me, cookies, javascript, etc.

OK, if it doesn't want me, I don't want it. I've got a life already.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

I thought Mr. Knowitall didn't use Spice ?:-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

       Make the world a better place, dismember a Democrat.

Maybe. Helmut can walk you thru the registration. I get the E-mailed digests. A lot of interesting traffic useful to beginners to Spice. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

       Make the world a better place, dismember a Democrat.

Yes, looks like you use the "bv" behavioural voltage source then edit the Value line to read V={TEMP}/100 or some such.

You can read the help (from outside wine) using xchm.

Say, does anyone else get multi-core simulating under wine? I am sure I used to - I remember being suitably impressed - but now it appears I do not.

--

John Devereux

Ah, BV. I'd been trying to get the regular voltage source to recognize TEMP in an equation, but it doesn't like that.

A regular resistor does accept a value like

1 tc1=0.001

and, if I dump a constant 1 amp into that, I get 1 volt with a tc of

+1 mV per degree C, which is my current workaround.

I'll try the BV thing. Thanks. I don't use LT Spice often enough to remember the subtleties.

I'm stuck at home today. The Giants are having a parade down Market Street, and it's impossible to get to work, so I'm doing some futzing with a circuit to compensate for photodiode leakages vs temperature.

They wanted to do the ticker-tape thing, but nobody makes ticker tape any more, and very few of the office building windows still open anyhow.

John

"John Larkin" schrieb im Newsbeitrag news: snipped-for-privacy@4ax.com...

Hello John,

You could also use a resistor with e.g. 1Ohm tc=0.001 fed by a 1A current source. This will give you a source with 1V, 1Ohm output resistance and a tc of

+1mV/°C. I you need zero Ohm output resistance, you could buffer it with an E-source with gain 1.

Best regards, Helmut

It's been awhile, but isn't the behavioral variable "temperature" rather than "temp", and don't forget the curly brackets (or whatever the LTspice equivalent is). ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

       Make the world a better place, dismember a Democrat.

"Jim Thompson" schrieb im Newsbeitrag news: snipped-for-privacy@4ax.com...

Hello Jim,

temp or TEMP is the temperature parameter of LTspice like in any other SPICE.

One can change it with a .TEMP directive or with .step TEMP

.TEMP 10 25 35 50

or

.step TEMP10 50 15

Best regards, Helmut

I did find TEMP inside a behavioral expression, as in {TEMP+273}, so I'd guess Larkin's error was lack of curly brackets.

I've used it in behavioral voltage sources to place specification brackets around, for example, 10K/100K PECL swings. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

       Make the world a better place, dismember a Democrat.

--
Edit the file to make it do want it to, and then run it.

And you think LT Spice help *is* great?

As usual, you make very little sense. You're just miffed at how the Giants took the Rangers apart.

John

You mean... You mean... You mean... You mean...

Larkin is an Obama clone ?:-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

       Make the world a better place, dismember a Democrat.

--
Not quite...

That is, I don't think he's black.

--
It's better than nothing, and then, of course, there's the manual, at:

http://ltspice.linear.com/software/scad3.pdf

then Helmut's group, at:

http://groups.yahoo.com/group/LTspice/