Yes, so that raises the question, just what is an 'expert' ?. 'A drip under pressure' is one answer, jokes aside there are other answers
Dan.
Yes, I do not dispute the more general form but the simpler layman definition allows for Ed's wording as similarly stated in Wkikipedia : Electrical_resistance_and_conductance#Ohm's_law
"For many materials, the current I through the material is proportional to the voltage V applied across it over a wide range of voltages and currents. Therefore, the resistance and conductance of objects or electronic components made of these materials is constant. This relationship is called Ohm's law, and materials which obey it are called ohmic materials. Examples of ohmic components are wires and resistors. The current-voltage (IV) graph of an ohmic device consists of a straight line through the origin with positive slope.
Other components and materials used in electronics do not obey Ohm's law; the current is not proportional to the voltage, so the resistance varies with the voltage and current through them. These are called nonlinear or nonohmic. Examples include diodes and fluorescent lamps. The IV curve of a nonohmic device is a curved line."
It's simply a different terminology, not different physics. 🙂
I for one am glad that there's a lock on edits after 30 minutes here.
John, Dan, when you can't prove a point, it's always best to attack and undermine those who are grounded in the way the world works, at least as far as how electrons behave.
The bar for expertise in the late conversation it's pretty low: namely having a firm grasp in nodal/mesh analysis of complex impedances.
Scott: e- charge and voltage all the way down to the turtles. 😉
John, Dan, when you can't prove a point, it's always best to attack and undermine those who are grounded in the way the world works, at least as far as how electrons behave.
The bar for expertise in the late conversation it's pretty low: namely having a firm grasp in nodal/mesh analysis of complex impedances.
Scott: e- charge and voltage all the way down to the turtles. 😉
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Perhaps different in different parts of the world, but I've met enough bright technicians who may have lacked the formal education. And with no chip on their shoulders to boot. 🙂
I much prefer to let people shoot themselves in the foot all by themselves, regardless their bonafides. 🙂
I much prefer to let people shoot themselves in the foot all by themselves, regardless their bonafides. 🙂
But non of the answers to that question would be "German minister of Education".
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There’s enough good scientists/engineers in the UK who did engineering apprenticeships and coupled that to a degree. I think Paul Dirac was one of them, as was Frank Whittle (think of him next time you fly in an airplane).
Intellectual arrogance and imperiously have no place on a DIY forum.
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What I mean is the confusing term "Ohmic". If something is "non-ohmic", it does not mean it violates Ohm's law at all. This would be a great oversimplification (of Ohm's law). University education helps talented people not to oversimplify and to find wider connections and supports abstract thinking. This is a fact (to me) and this is what I meant. You may call me arrogant, if you like.
For you it is an improvement. For others it can be just differences. Worse, some don't even think there's audible difference. For me, it is simply a trade-off, and I chose not to add the extra resistances. Any good things related with the extra resistances (or any bad things related to the absence of it) I will solve in a different way requiring less or no compromise.
And? According to my limited knowledge (which is subjective), it is a very basic thing (High School Physics). But the way you express your things have always made me think hard, "Is there something new here that I haven't already know?" And I still don't have the answer but I don't want to draw any conclusion 🙂
Bill,
There is 8 minutes between my post and yours, the presentation is 50 minutes more than that! You haven't even rounded the corner, let alone reached the end, so how do you know it is dead. Much to learn, even if you don't share the conclusions.
Vac
Edit: I only share his questions, from the point of view that there is no likely explanation for the prebiotic stage in ambiogenics. The answers are anybodies guess, mine are much more colourful than his.
There is 8 minutes between my post and yours, the presentation is 50 minutes more than that! You haven't even rounded the corner, let alone reached the end, so how do you know it is dead. Much to learn, even if you don't share the conclusions.
Vac
Edit: I only share his questions, from the point of view that there is no likely explanation for the prebiotic stage in ambiogenics. The answers are anybodies guess, mine are much more colourful than his.
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I meant the discussion petered out on here some 100s of posts ago and with no reminder or introduction you dumped it on us. It's also close enough to religion that its awkward to discuss on here.
I agree that it is an oversimplification. However, we find statements such as "elements as ohmic (obeys Ohm’s Law) or non-ohmic (doesn’t obey Ohm’s Law; also called nonlinear)." in handouts from Physics Department of University of Cincinnati and similar from others such as Harvard University and University of Mississippi to name a few. The wording has already been used pervasively on some community. What I'm saying is that the blame is not on Ed but his Professor.
No, it is science (the questions, not the answers), and I shared it because a friend sent me a link.
Edit: I meant of course abiogenesis in my earlier post.
Edit: I meant of course abiogenesis in my earlier post.
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It's given in a church and sponsored by a think tank that promotes the idea of intelligent design. If we were in a pub I'd be happy to discuss, but here in bear pen I'm personally uncomfortable with where it might go. I will watch the video though, even with my upfront bias that it won't change my mind.
FWIW I should also note that I consider Dawkins to be a dangerious fanatic.
FWIW I should also note that I consider Dawkins to be a dangerious fanatic.
I think he's worried about the load the amp sees, I can't see any change at the driver terminals, I could be wrong, I stopped reading his posts a while back.
Does that mean that there could be ME who have never seen Newton's laws? How can an engineering course put the foundations in an elective module?jneutron said:
As Ohm's law is not a law but merely a summary of common behaviour you cannot violate it. You can either follow it (e.g. most metals) or ignore it (e.g. semiconductors).PMA said:
No. Ohm's law says that for a given substance/item the current and voltage are proportional i.e. the ratio between current and voltage is a constant. This is true for many conductors and can be explained, but it is not a law of physics (unlike, for example, Kirchoff's laws). To establish whether Ohm's law is true for a substance/item you need to do more than one measurement; having established that it is true then you can use it at an instant.
True, but irrelevant. Ohm's law does not outlaw variable resistors, but it simply insists that for a given resistor in a given state (e.g. constant illumination, temperature) the current and the voltage must be proportional.
Yes, it simply ignores Ohm's law.
Ohm's law only applies to ohmic devices. The vector/tensor form of Ohm's law is the same. V=IR is only an expression of Ohm's law when R is independent of V and I. If R is a function of V or I then the device is not ohmic, Ohm's law does not apply, and V=IR is merely a way of calculating the value of R at that V and I. If you divide a current into a voltage then you will always get a result with the dimensions of resistance, but this does not mean that it is always meaningful or useful to call it a resistance in non-ohmic situations.syn08 said:
Not sure that is true. He did study engineering, but at Bristol University. See Wikipedia. He then did a maths degree at Bristol.Bonsai said:
“FWIW I should also note that I consider Dawkins to be a dangerious fanatic.”
Really? He’s a bit of a bulldog but I’d not put him in the dangerous fanatic box but maybe you know something about him I don’t.
Maybe I am confusing Dirac with someone else. 🙂
Really? He’s a bit of a bulldog but I’d not put him in the dangerous fanatic box but maybe you know something about him I don’t.
Maybe I am confusing Dirac with someone else. 🙂
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