Update: Varistor/MOV Spice Modeling

After you get well, you're welcome to try.

On a related note then, if anyone has something they'd like to model, I could take a crack at it.

I suspect Jim isn't doing anything I don't know, and if he sees some examples, maybe he'd even admit what it is, too ;-)

Tim

Perhaps not the right place in the thread to say this, but what problems would come up if you modelled a varistor as a behavioural current source with I = k* V^alpha in series with a bulk resistance? I've had pretty good luck with that model (just not in SPICE).

I'm seeing interst in the model, rather than in _using_ the model.

Bwahahahahahaha! I needed a laugh right now.

How about an NCP1072? That was requested on the LTspice List >:-} ...Jim Thompson

How about a resistor, diode, voltage source?

A couple in parallel if you want some curvature.

Bridge rectifier if you need bipolar.

There's not a lot of demand for an accurate MOV model, especially an encrypted one.

Someone with a "B" (Beckman? Bourns?) used to sell a "precision" MOV. Its i-v curve was a square or an exponential or something, and it could in theory be used to do analog computing, multipliers and such. Given that MOVs are not stable and have a lot of capacitance, it was a silly idea that soon disappeared.

There was a request on the LTspice List and I provided a model.

Why do you have heartburn over "encrypted"?

The model is completely general. All the parameters (fill-in the blanks) are available straight off of most datasheets. ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

You keep telling us how smart you are, and how dumb we are, and all we need to do is take your word for it.

Why are you keeping it a secret? Paranoia or insecurity?

Huh? Where did I say that?

Why do you insist on being a psychopathic asshole? ...Jim Thompson

Oooops! I already know the answer... because you ARE >:-} ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

OK, insecurity. If people saw what you did, they might criticize. Or have a better idea.

Better keep it a secret.

The LT Spice "g" componant is a voltage dependant current source. The relationship could be your equation, or a polynomial, or anything. That would be *one* line of text. Add capacitance or ESL as needed.

Are you really so ignorant to believe that? I guess that's the way psychopathic assholes think. ...Jim Thompson

Yep. The MOV equation is one line of GVALUE... with coefficients set by VTEST, ITEST, VCLAMP, ICLAMP, Rseries, Lseries and Cpar, right from the data sheet.

But apparently too difficult for Larkin the psychopathic asshole to master plugging in the numbers. ...Jim Thompson

One line? What line? This one maybe?

You will NEVER see the equation, as simple as it is, NEVER >:-} ...Jim Thompson

Oh no, no, I'm heartbroken.

Good >:-} ...Jim Thompson