On Mon, 17 Mar 2014 12:27:44 -0500, Tim Wescott
wrote:

On Sun, 16 Mar 2014 11:20:38 -0700, Jim Thompson wrote:

On Sun, 16 Mar 2014 13:59:29 -0400, Phil Hobbs
wrote:

On 3/16/2014 1:39 PM, Jim Thompson wrote:
Anyone have an accurate I-V curve for an NE-2 neon indicator lamp?

(I think it's time I applied TANH to it ;-)

...Jim Thompson


Of course tanh is single-valued, unlike the I-V of a NE2.

Cheers

Phil Hobbs

Unless you are clever, like me :-}

Look back over my piece-wise-linear curve-fitting posts, using TANH,
with all derivatives existing and finite.

In this particular case, as I envision it, there are not even any
break-points involved.

What I seek right now is a reasonably accurate I-V curve.

I can't tell if you're being purposely coy, or if you've missed Phil's
point.

Gas discharge devices like neon lamps have hysteresis: when they're on,
they'll conduct at a lower voltage than their turn-on voltage.

Missed adding, when I posted my simulation curve: Gas discharge
devices don't have hysteresis, except perhaps a very small amount in
the ionizing/quenching process (and, of course, temperature), but they
_do_ have a negative resistance region... see my other post...

Subject: NE-2 I-V Curve ??
Date: Mon, 17 Mar 2014 16:47:19 -0700
Message-ID:


So a simple I-V curve doesn't cut it, unless you're only trying to
simulate the device in the on state, and leaving the user out to dry for
figuring out turn-on and turn-off behavior.

Sounds like you let LTspice mislead you with its
switches-with-hysteresis model?

Looks like there's also some confusion here about TANH curves and
TANH-based switch models. TANH-based switch models converge much
better, but have absolutely nothing to do with neon gas discharge
behavior.

...Jim Thompson
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