LT spice Introduction, Setting Up, Updating

LT spice, Curve Captor, PSUDII and whatever other sims you can think of.

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LT spice Introduction, Setting Up, Updating

Post by sbench »

Here's an introduction to a great modeling tool, Linear Technologies LTC Spice. Go to the Linear Technologies site to download and install this program. ( --- on the main page there will be a link to "free download of switchercad")

A lot of this is on Duncan Munro's site, but for more or less completeness, here's how to add tube Spice modeling to LT Spice. LT Spice is freeware available for the download at Linear Technology's web site. It is a complete Spice that has NOT been wounded, limited or disabled in any way.

In the swcadiii directory (that's the default where all the schematics you create reside - usually under "Program Files" and LTC or whatever) place the include files. Attached here are and

You need to add a Spice Directive .INC onto your schematic to actually USE it.

Now go down into lib/sym/misc folder and add the tube symbols

That's all the overall files you need. To add a tube go to add component, misc and you should find the triode, tetrode etc symbols. Add that to your schematic, and call the "right" tube. (right click the symbol to bring up the attributes, set "value" to one of the values listed below.)

the dmtriodep include file models
NH2A3 virtual filament model
NH3CX300 no heater model
NHSV6AS7 no heater model
NH6BM8 no heater, triode section only
NH6DJ8 no heater model
NH6N1P no heater model
NH6SN7GTB no heater model
NHD3a also called 7721 My model, no heater, triode conn with g3 to K
NH12AT7 no heater model
NH12AU7 no heater model
NH12AX7 no heater model
NH76 no heater model
NH300B virtual cathode, no filament model
SV5723 SV572-3 virtual cathode, no filament model
SV57210 SV572-10 virtual cathode, no filament model
NH5751 no heater model

There's more on Duncan's site, but this is all I need for info presented here at this point. The D3a/7721 model is mine and close enough for government work.

LTSpice stuff files attached...

The file DMTRIODEP.INC in the ZIP file also has a global PARAM added to it as described in another post. That PARAM (EMISSIONRANGE) alters one formula in each of TRIODE and TRIODENH subcircuits. The default EMISSIONRANGE value (1) makes the formula identical with Duncan's original files. See the section on effects of tube degradation on how to use this.

**** note **** I've updated in the SPICE.ZIP file. The 2A3 was fatally flawed in the original.

LT Spice has the facility of keeping you up to date with the latest bug fixes, models etc. Since it's free, it is wise to periodically make sure your version is up to date.

Under TOOLS is a "synchronize release" selection. This automatically queries the Linear Technology web site for updates and automatically handles them.

There are several folders in this SPICE section to tell you about some nice features in LTC Spice.

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