RE: Gap Question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Luke" <Bluu-at-cox-dot-net> 

Can anyone point me to a device that does not have a linear resistance
but yet does not display a negative resistance?
Is there such an animal?

Thanx

Luke Galyan
Bluu-at-cox-dot-net
http://members.cox-dot-net/bluu

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, February 26, 2004 5:34 PM
To: tesla-at-pupman-dot-com
Subject: RE: Gap Question

Original poster: "Luke" <Bluu-at-cox-dot-net>

Ok I see what you are saying.
Thanx
This is starting to click a bit.

This has been a very enlightening topic for me!!

I was used to thinking of resistance as something the hinders the flow
of electricity.  I know that is what it normally means.  But I was not
used to the term being made to refer to the V I properties and not
thought of as actual resistance per say.

And yup I see what you mean in the lower graph the resistance decreases
but the slope does not go negative.

So as well as learning some other stuff here I finally came to grips
with the word resistance in the term negative resistance is not
referring to actual resistance even though the V I can be used to
calculate a resistance.

Thanx.

Luke Galyan
Bluu-at-cox-dot-net
http://members.cox-dot-net/bluu

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, February 26, 2004 7:19 AM
To: tesla-at-pupman-dot-com
Subject: Re: Gap Question

Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>

Tesla list wrote:

   > Is it safe to say that a device that displays negative resistance,
   > refers to a components ohmic value decreasing when there is an
increase
   > of voltage or current?  And yes I realize that this would only occur
at
   > certain areas on the V I curve.

Use a fixed-width font to see the pictures.
Negative resistance occurs when the voltage decreases and the current
increases, or when the slope of the i x v curve is negative.

|i         /      |i                /
|         /       |                /
|        /        |               /
|        \        |              /
|         \ here  |      here   /
|          \      |    /\      /
|        __/      |   /  \    /
|     __/         |  /    \  /
|  __/            | /      \/
|_/          v    |/                  v
+-------------    +--------------------

It's not safe to define as Ohmic value i/v. In the negative resistance
region of the curves above it decreases as the voltage decreases, but
it does the same in the curve below, that doesn't have a negative
resistance area:

|i              /
|              /
|             /
|    ________/
|   /
|  /
| /
|/                v
+------------------

So, reserve the term "resistance" for linear resistors, or to measure
the slope of the i x v curve.

Antonio Carlos M. de Queiroz