Recent content by Landru

  1. L

    How does RFI manifest in the audio range?

    So I understand that grounded shielding of audio equipment is necessary to block both EMI and RFI from audio equipment, but what I can't find information about is how, for example, radio frequency interference "RFI" at 150kHz, can interfere with audio equipment in such a way that you will hear...
  2. L

    Line impedance versus shunt capacitance

    Thanks for making that demo. Between your response and and tech99's post it makes good sense now. So the issue is that a high impedance causes the capacitance to become a "path of least resistance" as frequency rises, where as a low impedance deprives the capacitance of that opportunity to...
  3. L

    Line impedance versus shunt capacitance

    Hello, I'm having the damnedest time wrapping my head around a concept of audio electronics: http://whirlwindusa.com/support/tech-articles/high-and-low-impedance-signals/ How exactly does a higher impedance bring down the frequency at which capacitance dominates? My current understanding is...
  4. L

    Electrostatic/electromagnetic noise and conductive area

    I play electric guitar, and electromagnetic noise is a big concern for us. There are two types of noise, those that arrive as magnetic fields and those that arrive as electrical fields. This web page is a resource from which I've derived this understanding...
  5. L

    Question regarding Faraday's law on induction

    So what you're saying is that it's not enough that the flux increase, but that the flux increase must share a common polarity, and if they don't, they cancel as if there was no flux increase at all?
  6. L

    Question regarding Faraday's law on induction

    The law states: So, what if the change is flux changes are proportionately equal parts of opposite polarities? Suppose you approach a coil with two magnets on either side of the coil, each set to repel each other's north or south faces; the flux increases, but in equal parts opposite polarity...
  7. L

    Can LTSpice's .ac statement sweep secondary values?

    If you have a simple circuit with an AC voltage, you can do a frequency domain analysis with a statement like ".ac lin 500 10 10000" and it will run the gamut from 10Hz to 10000Hz, but is there a way to have a second variable also scale in tandem, say the value of a resistor? I'm aware that the...
  8. L

    Permeable coil cores; what's actually happening?

    In descriptions of how an electrical transformer works, I've seen it said that the permeable core "conducts a magnetic field" or "allows magnetism to pass through better than it passes through air", but isn't that description misleading? Isn't it really the case that the permeable material's...
  9. L

    B Does "nothing" have a meaning in physics?

    Can you give an example of where the distinction becomes important?
  10. L

    B Does "nothing" have a meaning in physics?

    The important thing to know is that "null" is not the same as "zero", "no value" versus "a value of zero", and so the meaning of "nothing" depends on which more specific word or definition it's making reference to.
  11. L

    How do magnetic "return paths" really work?

    AFAIK, the hysteresis curve is caused by the (un)willingness of the magnetic domains in the ferrous material to align, and/or re-align later, as is dictated by the particulars of the physical structure at the atomic level, but once they align, it is essentially a proper magnet from that point...
  12. L

    B Does "nothing" have a meaning in physics?

    Math is sometimes employed in physics, so there tends to be overlap.
  13. L

    B Does "nothing" have a meaning in physics?

    I think this is what you're looking for https://en.wikipedia.org/wiki/Null_(mathematics)
  14. L

    How do magnetic "return paths" really work?

    Do you have a source for this? The source I linked above did not mention caveats about magnetic flux lines only vector summing in non ferrous mediums. I've read that overlapping magnetic field obey the super position principle: https://en.wikipedia.org/wiki/Superposition_principle...
  15. L

    How do magnetic "return paths" really work?

    How can combining magnetic fields be simple vector addition if their fields are distorted? You'd no longer have "field A + field B", but "somehow distorted field A + somehow distorted field B". Does that make sense?
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