SPICE simulation of finite Q inductors

In most cases, the Q is important only near the resonant frequency. I use a single fixed value resistor in series with the L that sets the Q at the frequency corresponding to the circuit resonance frequency.

Mark

In critical applications I'm inclined to use a multi-lump model to make sure I catch any "squirrels" ;-)

...Jim Thompson

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Too bad you can't make that work on Usenet. We're overrun with squirrels. :(

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I've suddenly acquired jack rabbits in my front yard. Can't figure out where they're nesting.

...Jim Thompson

Be VERY careful, Jim. Eeyore sent them to spy on you!

THAT explains it ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

You better oil up your Uzi, he wants them to build a roundabout in your yard.

I think the greeting sign (in Hebrew) out on the front patio will probably drive him back ;-)

...Jim Thompson

Do you think that I should tell the little moron that I was trained to kill with the M16, the M60, and how to use the M72, yet I've never had to kill anyone?

I can't find the original message so I will continue here. The first order model should include the winding resistance as a series resistor, and then compute a parrallel resistor due to the core losses. Verify over the frequencies your interested in, materials vary a lot. In fact if a series resistance is sufficiently accurate, you can use pre-distortion (right term?), tilting the frequency axis, and design the filter having perfect (inf Q) components; and then undistort the results to get values. That sounds a little jumbled, but these days I presume that technique is obsolere. I reliably designed a 9 pole filter in the 70's this way; with both time and frequency requirements.

Ray

Coilcraft has some nice SPICE models for their inductors. You could modify one of those.

Leon

Coilcraft has some nice SPICE models for their inductors. You could modify one of those.

Leon

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Well, you might as well just accept them, and hope your plants grow faster than they can eat them... 8-)

Charlie

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I don't think they eat cactus or mesquite ?:-)

If they do, I'll just get out the shotgun ;-)

...Jim Thompson

If they eat cacti, ship them to Lake County Florida. There is enough there to feed millions of the willey wabbits down there. :(

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Young mesquite, probably. Cacti, they usually use to cover their burrows. The problems are if you have any flowers or food plants growning. In Borrego, we had several families, but there was only one of the plants that they liked so well that it couldn't grow. But, once we planted some marigolds. Lasted two days...

Charlie