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LTSpice: how to add a transformer?

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Michael

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Sep 19, 2007, 11:07:01 AM9/19/07
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Hi there - I'm trying to add a transformer to a LTSpice schematic. Can
anybody give me any suggestions as to how to go about doing this? I
can't find them anywhere! I remember in one circuit simulation program
I used years ago I had to couple two inductors to create a
transformer, but I can't even find such an option in the inductor
properties.

Thanks,

-Michael

Tom Bruhns

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Sep 19, 2007, 12:07:28 PM9/19/07
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You can just place two inductances and something like "K1 L1 L2
0.999" (text) next to them (or anywhere on the schematic, it's more
readable if it's close to the inductors involved). There are more
complicated models, including capacitance and resistance, of course,
and you can also create one using sources to emulate the coupling.

You should find at least a couple examples of transformers in the
examples/educational directory under LTSpice: transformer.asc and
transformer2.asc.

You'd do well to join the Yahoo group for LTSpice, where you will find
examples of transformers, discussions about transformer models, and
lots of helpful folk.

Cheers,
Tom

Joel Kolstad

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Sep 19, 2007, 12:16:27 PM9/19/07
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"Michael" <nlea...@gmail.com> wrote in message
news:1190214421.3...@w3g2000hsg.googlegroups.com...

> Hi there - I'm trying to add a transformer to a LTSpice schematic. Can
> anybody give me any suggestions as to how to go about doing this?

You add two inductors and then add a SPICE directive (Edit->SPICE directive)
along the lines of, "K1 L1 L2 0.99" which says L1 and L2 make up a transformer
with a coupling coefficient of 0.99. (And in case you don't recall: The turns
ratio goes with the square root of inductance -- if L1 is 1mH and L2 is 4mH,
L1 has "x" turns and L2 has "2x" turns.)

See the example: c:\program
files\ltc\swcadiii\examples\educational\transformer.asc. For a three-winding
transformer, there's transformer2.asc.

---Joel


Genome

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Sep 19, 2007, 4:33:48 PM9/19/07
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http://www.genomerics.talktalk.net/michael/resonhv.pdf

For blither.... ouch...

http://www.genomerics.talktalk.net/michael/core.asc
http://www.genomerics.talktalk.net/michael/winding.asc

For schematics

http://www.genomerics.talktalk.net/michael/core.asy
http://www.genomerics.talktalk.net/michael/winding.asy

For symbols.

DNA

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