Do you think an LED is a resistor?

[Sredni]

I believe this is the sixth time I have to repeat it: in all this discussion I am neglecting parasitic effects. Because I am discussing the FUNDAMENTAL nature of the diode.

A silicon diode described by the exponential Shockley relation, with negligible junction capacitance and negligible inductance of its terminals is FUNDAMENTALLY just a nonlinear resistor, that is: a resistor whose resistance is a function of its voltage.
I also showed the R = R(V) curve in LTSpice.

It does nothing more than that. The nonlinear resistance is its primary and intended function. It is what it makes it a diode.
Unlike the ESR of capacitors and inductors, which is only an undesirable parasitics.

[PlainName]

It is what it makes it a diode

That's what you  keep getting told. A diode has non-linear resistance. A resistor has linear resistance.

[Sredni]

It is what it makes it a diode

That's what you  keep getting told. A diode has non-linear resistance. A resistor has linear resistance.

So you agree that a diode is a nonlinear resistor.

But you don't think that nonlinear resistors are... resistors. Correct?

[Zero999]

Non-linear resistors are not resistors. They are something else: diodes, DIACs, varistors etc. but not resistors. End of discussion.

[tom66]

This whole thread is a meaningless semantic argument, ultimately why does it matter if you want to go against the grain of most engineering and call a diode a resistor with non-linear properties then go ahead... but does it have any use in the real world?  No, it does not.  You can define a diode by a Vf and a few other basic parameters and get a useful result that is close to real world behaviour, but you cannot usefully define a diode by a resistance as the apparent "resistance" varies significantly across the V/I curve.  End of argument.  I really can't believe this has gone on for 9 pages.

[Sredni]

This whole thread is a meaningless semantic argument, ultimately why does it matter if you want to go against the grain of most engineering and call a diode a resistor with non-linear properties then go ahead... but does it have any use in the real world?  No, it does not.  You can define a diode by a Vf and a few other basic parameters and get a useful result that is close to real world behaviour, but you cannot usefully define a diode by a resistance as the apparent "resistance" varies significantly across the V/I curve.  End of argument.  I really can't believe this has gone on for 9 pages.

"Most engineering"? Are you sure that 'most engineering' do not realize the diode is a nonlinear resistor? I mean you can bring a load of vocational school books that do not need to go any further than a superficial hands-on description of the devices, but when it comes to serious engineering books, and even more so circuit theory books, and even more so nonlinear circuits theory books, it is glaring evident that a diode is a nonlinear resistor.

Even mainstream references, like "The Electrical Engineering Handbook" leave no room to ambiguities:

Nonlinear resistors commonly used in electronic circuits are diodes: exponential, zener, and tunnel (Esaki) diodes.

Maybe you can call Elsevier, or Simon Fraser university and tell the author of that chapter that they are going against the grain of 'most engineering'.

It took 9 pages because the objection shifted from "if it's a diode its not a resistor, duh", to "there is no such thing as a nonlinear resistor", to "nonlinear resistors exists but they can only be varistors, lamps, but not diodes", to "diodes are nonlinear resistors but nonlinear resistors are not resistors".

Edit: grammar

[MK14]

Bold and font size change, done by me.

I am curious. How many of you people think an LED is a resistor? I should add: from the point of view of circuit theory, not from that of technology and underlying physics.

(This question originates from a question in another forum, where polls are not possible).

You specifically said "resistor", in the poll.

So you can't start changing the "resistor" to other things, such as "non-linear" resistors, later in the thread.

Because it makes the poll (and possibly the thread), relatively meaningless.

[Sredni]

A nonlinear RESISTOR is a RESISTOR.

nonlinear here is an adjective that specifies a particular property of a subset of the general set of resistors.

A bald man is a man.
A one-legged man is still a man, even if in all medicine books the body of a man is shown with two legs.

A nonlinear inductor is still an inductor.
The inductors used in Single Ended Primary Inductor Converters are usually nonlinear but they are called inductors nonetheless. Have you ever read "the nonlinear coil two-port element's current is..." In the description of a switching circuit? No, everybody says "the inductor's current..."

Sheesh...

[Gyro]

This is getting nobody anywhere...

In the real world, semiconductors, including diodes (of all flavors) have datasheets. These specify the typical and worst case voltage / current characteristics under defined conditions. People find these USEFUL in designing them into circuits and products in the real world. Your dogmatic semantic argument that they are all resistors is NOT USEFUL in the real world. See the distinction?

Your dinner tonight will have electrical resistance, which will be determined by its composition temperature etc. as will the plate it is sitting on, the table they are sitting on, the chair you are sitting on (and the arse you're sitting on it with). Will you sit there making semantic arguments that they should all be defined as resistors until it gets cold (or in your case possibly moldy), or in the real world, will you just eat it?

[MK14]

A nonlinear RESISTOR is a RESISTOR.

nonlinear here is an adjective that specifies a particular property of a subset of the general set of resistors.

If someone in an opening forum post, says "Resistor".  That should mean a component, which obeys (without any trickery or messing around) Ohms Law.  So it can't be a non-linear thing.

If it is (or could be something) which doesn't obey Ohms Law and/or a weird type of resistor.  Then that should be clearly stated in the opening post/poll.

Otherwise, you are moving into the realms of (similar to), trick questions.

When making polls, it is very important that the question(s) and propositions etc.  Are very unambiguous, to a very wide audience.  Otherwise the poll results and possibly the thread, may just descend into massive arguments.

[bdunham7]

A bald man is a man.
A one-legged man is still a man, even if in all medicine books the body of a man is shown with two legs.

How about a fictional man?  Or a robotic man?  An AI man?  A virtual man? 

As I clearly explained earlier--and you appear to have used the concepts I explained and twisted them around to your own ends--something described by an adjective plus a noun does not necessarily belong to the set of things described by the noun alone.  So it all boils down to how you choose to define resistor.  And stop with the bleating that these aren't YOUR definitions but rather those of some famous people we're bound to respect--you don't have to invent the descriptions, they become "yours" if you choose to adopt them.  My definition of convenience is that the term 'resistor' used alone with no prefix means a fixed, nominally linear resistor.  I didn't invent that.

Wikipedia has an interesting statement--"The electrical function of a resistor is specified by its resistance".  I like that.  Is an LED's function specified by a resistance value?  There's an opening for you in that statement, perhaps you'll get another 9 pages out of it.