From: PaulJK on
Hatunen wrote:
> On Wed, 31 Mar 2010 17:32:24 +1200, "PaulJK"
> <paul.kriha(a)paradise.net.nz> wrote:
>
>> Hatunen wrote:
>
>>> There's no gap in a semiconductor diode....
>>
>> You can view the P-N junction as a kind of an equivalent of
>> a gap.
>
> "Kind of equivalent"? Now there's a precise technical term.

You are right, and it's mine.
From now on let it be known as Kind Of Equivalent® or KOE®

>> It also breaks catastrophically when certain voltage
>> is reached.
>
> Almost everything will break catastrophically when a certain
> voltage is reached. I should think we are dealing in operation
> within the stated safe parameters here.

Sorry, I thought while talking about popping diods we
were talking about extreme conditions.

pjk

From: Glenn Knickerbocker on
On Wed, 31 Mar 2010 21:38:46 +0000 (UTC), Bryce Utting wrote:
>Glenn Knickerbocker <NotR(a)bestweb.net> wrote:
>> On 03/31/2010 05:55 AM, Bryce Utting wrote:
>>> BUT WHERE ARE THE SCREAMING HIPPOS OF DEATH?!!
>> Lyndhurst Road, Worthing.
>well, that's no good -- BT are headquartered on Newgate Street, in the
>City of London.

Is 12 Coleridge Close, Climthorpe near enough?

�R http://users.bestweb.net/~notr You are already too educated stupid to
understand the truth of nature's harmonic simultaneous 4-liter wine cube
From: Evan Kirshenbaum on
"PaulJK" <paul.kriha(a)paradise.net.nz> writes:

> Yes, Brian, I well understand their point of view.
> The disagreement is indeed as you say about what
> meaning should be assigned to the term 'Ohm's law'.
>
> What I (and some others in this thread) were taught was that Ohm's
> law was V=IR. (fullstop) No linearity is implied. It is equally
> applicable in conductors with variable non-linear
> resistance/reactance and equally applies in complex high frequency
> environments. It is obeyed and applicable everywhere in nature even
> in complex non-linear environments, like brain and nerves or in
> lightnings.
>
> I don't know if this was the way the law was understood by Ohm in
> its year naught, but that was the modern version of the law I was
> taught and used in differential equations, Laplace and Z transforms
> describing the behaviour of the el.circuits.

It apparently wasn't the way the law was understood by, among others,
Maxwell:

The statement of Ohm's law is that, for a conductor in a given
state, the electromotive force is proportional to the current
produced. The quotient of the numerical value of the
electromotive force divided by the numerical value of the current
is defined as the resistance of the conductor; and Ohm's law
asserts that the resistance, as thus defined, does not vary with
the strength of the current.

Report of the Committee, consisting of Professor
Clerk Maxwell, Professor J.D. Everett, and
Dr. A. Schuster, for Testing Experimentally
Ohm's Law, _Report of the Forty-Sixth Meeting of
the British Association for the Advancement of
Science_, 1876.

Their conclusion was that, within the limits of experimental error, it
appeared to be true. Just a few years later I see people talking
about violations of Ohm's Law, also implying that it requires
linearity, e.g.,

.... which does not conduct according to Ohm's law, but with a
resistance deminishing as the electromotive force increases.

J. Hopkinson, _The Telegraphic Journal_, August
1, 1879

This is still the way it's stated in textbooks in the twentieth
century:

78. Ohm's Law.--When an e.m.f. is applied to the terminals of a
conductor, a current is produced which is directly proportional to
the e.m.f. and is inversely proportional to the resistance of the
conductor.
Clarence Christie, _Electrical Engineering_,
1917

> The reason for my disagreeing with "them" is not for the
> lack of attention, we simply disagree on that fundamental
> level of what is and isn't Ohm's law.

Can you point to something published that describes Ohm's Law without
implying linearity?

--
Evan Kirshenbaum +------------------------------------
HP Laboratories |When correctly viewed,
1501 Page Mill Road, 1U, MS 1141 | Everything is lewd.
Palo Alto, CA 94304 |I could tell you things
| about Peter Pan,
kirshenbaum(a)hpl.hp.com |and the Wizard of Oz--
(650)857-7572 | there's a dirty old man!
| Tom Lehrer
http://www.kirshenbaum.net/
From: Mike Barnes on
PaulJK <paul.kriha(a)paradise.net.nz>:
>Otto Bahn wrote:
>>If you always warm up you light bulbs before turning
>> them on, they last longer, but it's cheaper just to buy a
>> new bulb now and then.
>
>:-)
>I am not quite sure what kind of device you'd use to warm
>the bulb's filament to at least 1200�C.
>
>It might be cheaper to use a variable resistor to increase
>the power in about a quarter of a second, or use the
>commercially available light dimmers. It's still cheaper
>to change each 50� - $1.00 bulb once every few years.

Filament bulbs? You guys are *so* twentieth century.

--
Mike Barnes
Cheshire, England
From: Mark Edwards on
No cluons were harmed when Mike Barnes wrote:
>Filament bulbs? You guys are *so* twentieth century.

No kidding. I stopped using fillum when I bought my first digital.


Mark Edwards
--
Proof of Sanity Forged Upon Request