I was told on here by benb that mu-metal affects EMI (magnetism).
Yes, sorry, I meant increase.
Please pardon me but you were talking about stray capacitance, but now you say stray inductance, not parasitic inductance in relation to the use of mu-metal? Confused now? Sorry!
BTW: I cannot find my posts regarding long lead insulation - sorry!
...anyway, if a long lead IS insulated from EMI/RFI does it always need to be earthed/grounded?
For example: My mains cables have 2 insulators, a braid that is earthed to the plug terminal, either at one end or both, but it also has a kind of copper foil running the full length of the cable which IS NOT earthed at either end (manufactured product, not created by me).
For example: My mains cables have 2 insulators, a braid that is earthed to the plug terminal, either at one end or both, but it also has a kind of copper foil running the full length of the cable which IS NOT earthed at either end (manufactured product, not created by me).
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YES! ~ I edited my error based on your knowledge, I thought I was learning from you, but perhaps you are a useless teacher and/or I was labouring under a misapprehension?
I corrected my error/mistake based on your advice, I HAVE NO PROBLEM ADMITTING THAT! ~ What is your problem? Perhaps it's simply cheap one-upmanship or perverse childish 'point scoring' of some kind to impress your peers on this forum?
I think you are right to suggest a textbook is 'better', because it is neutral and impartial and above all does not answer back with cheap disagreements over semantics!
Did you read post259?R U going to help me get it then, or just mock and drool?
I took the time to type out the answers you now claim I did not give.
an outer conductive layer that is unconnected does nothing except increase the cost of the cable.
For a screen/shield to be effective it needs to be connected to the enclosure or to a low impedance reference point.
The interference has to be given an alternative route rather than imposing itself on the signal conductor.
Stray inductance and parasitic inductance are the same thing. Mu-metal is only used when a magnetic-field-sensitive component (e.g. input transformer) has to be shielded from magnetic fields. It is not very effective when put around the source of those fields as mu-metal saturates at quite low field strengths.thedoc735 said:
Insulation does not prevent EMI/RFI. However, you may have been using 'insulated' in the more general meaning of 'isolated' or 'protected'; earthing/grounding may be part of the method of protecting it, or it may not - depends on type of cable and context.
Mains cables do not need shielding. It is not possible to answer technical questions based on false premises.
A quote should be a quote, even when quoting yourself. You can add comments to a quote, including corrections, but unflagged modifications turn it into a misquote. Do you not understand the common rules of discussion: don't misquote people, including yourself? This is not 'point scoring', and I have no need to impress anyone.
DF96 says he is only concerned with facts about electronics, but it seems to me that there are plenty of posts here that have absolutely nothing to do with facts and EVERYTHING to do with pointing out my personal errors and contradictions which just serves to confuse me even more! Which you would not find in a text book because the author has never interacted with me on any level, i.e. hopefully pure knowledge about the subject without comments about my personal forum statements or attempted corrections thereof, which is just a waste of time and space; just tell me what I need to know without all this flack!
you see what I mean exact wording doesn't matter: "Stray inductance and parasitic inductance are the same thing."
"Insulation does not prevent EMI/RFI". However, there are dozens of people selling copper EMI/RFI shielding tape on ebay! (stating that it does).
"Mains cables do not need shielding". However there are many double shielded mains cables for sale just like the viablue x-25?
BTW: even a text book is secondhand knowledge which I have been force fed and 'groomed' by the author (brainwashed) into his way of thinking! In as much as; I have not learned, realised, experienced, experimented, discovered (myself) firsthand, but replied upon the experience of the author which we presume to be correct and accurate! Having said that, in my life time I HAVE found errors in textbooks! I used to highlight them and put them back on the shelf in the library! Not all text books therefore are the last word and testament on any given subject! Do you concur? 😎
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No, I used two phrases which mean the same thing. You used a phrase which means nothing. Can you understand the difference between a synonym and meaninglessness?thedoc735 said:
Copper is not an insulator!! Do you understand the meaning of any of the words you use?
And doubtless there are lots of ignorant people to buy such useless items. At best they simply do what any mains cable does: get power safely to the equipment. At worst they either increase RFI (some have an ungrounded 'shield') or introduce electrical safety hazards.
Would you prefer to have your errors and contradictions left unchallenged? If so, the discussion would have to end as there would be no basis for intelligent communication. You would still be confused, but less aware of this. On this forum nonsense is challenged; I understand there may be other audio websites where nonsense is welcomed and celebrated.
I suggest a little humility would help. Start listening and start learning.
Textbooks may contain errors: yes.thedoc735 said:
Reading a textbook causes brainwashing? Nonsense. One is supposed to read a textbook with all critical faculties in play. Having said that, nine times out of ten if the reader disagrees with the author then it is the reader who lacks understanding.
DF96; don't get me wrong, I respect your apparent consummate ability and knowledge but find your attitude to those with lesser knowledge somewhat belittling, demeaning and condescending! The downside to contact forums (like this one) is that it allows far too much personal ego to surface which detracts from the actual subject matter. By contrast, a book allows NO PERSONAL CONTACT what-so-ever, you simply read, read, read and hope to god that it is correct! No offence intended.
But if you read in any book something that you know is wrong, then you simply ignore it, because usually it is typo or errata during the printing. For example, the book from van der Veen, ha said power is E²*R, and in the example becomes E²/R. So, imaginary you say "This guy is wrong", and simply continue reading.
It is still worse when you read or listen stupidities from a person. When pupil in certain Argentine University, when a professor said things wrong, and you can't correct it because he then revenges in the following exam, don't finishing the course never more.
It is still worse when you read or listen stupidities from a person. When pupil in certain Argentine University, when a professor said things wrong, and you can't correct it because he then revenges in the following exam, don't finishing the course never more.
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It's the main reason I hated public education a lot. You're aware of the teacher's mistakes, but you dare not challenge them and if you do, you get punished for it. You can't question the teacher's knowledge or authority. Even if he's wrong. What a dictatorship.
But it's made to work great for the masses. That, I can't deny.
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