Yes. Medical is exempt. Flight hardware, space hardware, undersea cable hardware, weapons hardware, as well as industrial control.
There are/were more exemptions, I've forgotten most.
But as marce pointed out, finding non lead free components is becoming harder. I hate to pre-dip components to remove the lead free coating, it's just another extreme temperature cycle to compromise the part longevity.
jn
There are a few left, Ti is good source for basic logic and some op-amps (not many current footprints or component sizes), I'm not sourcing, its a nucleonics' type job so all components from an approved list with some nice Ladies doing all that... security, guides, restrictions etc. make mil./aerospace seem a breeze... Usually everything goes in a hybrid and you just slap a few of them on a board and join the dots, so much easier.
Nope, lead does not leach out of solder very easily.... It was wider ranging than that, lead just got caught up in the excitement, did many a report with others to try and get lead solder exempt.
Medical devices are not exempt any more, since July 2014....
RoHS July 2014 deadline: medical devices and control instruments - Actio
Ah forgot about dipping, again like Jn sais it adds another thermal cycle, only allowed 3...
Industrial control is no longer exempt....
We are on RoHS 2 now.
Industrial control is no longer exempt....
We are on RoHS 2 now.
RF cables are not audio cables.... Different kettle of fish... a variation in the cables characteristic impedance will show up for both RF and high speed digital as a slight difference in reflections, nothing new, audio frequencies not really....
How do you vary the velocity of a signal in a particular cable? that's down to the cable construction and dielectric constant of the insulation.....
How do you vary the velocity of a signal in a particular cable? that's down to the cable construction and dielectric constant of the insulation.....
I was referring to some real sensible data from audio cable manufacturers, the opposite of say audioquest or synergestic research bunf.....
Bend the living daylights out of it. And as an added extra bonus, is splashes signal out into the environment.
For parallel pairs, run it through a metallic conduit. The permeability can slow it down.
I recall one vendor of speaker cables actually talking about stripline geometry with a varying dielectric thickess.
go figure..
jn
HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA! Oh wait, you're not joking?
Fred Davis. Dick Greiner. There's really nothing to add to their work. It was a trivial thing then (35 years ago) and even more trivial now. Only gullibility, cupidity, and a total lack of morals has kept the question alive in the tiny niche of fashion audio.
Hybrids..sigh..those were the days...
I remember working on the fastest memory module for a big customer. It was a screamer, 50 nSec static ram...
jn
Hello Simon.
Hmmm, power flow/transfer is singular direction, ie source to load, but the conductors required to complete any circuit carry current in alternation direction.
Audio signal peak values are asymmetric, but there is no net DC component in replay/reinforced audio due to HP filtering.
IOW the area under the curves for pos and neg signal polarities are identical, BUT signal pos and neg slew rates and peak values are NOT identical.
This could cause audio equipment differences due to sensitivities to induced noise pickup.
Interesting.
In the Naim cable example photo, I understand that the arrows are to enable easy identification of direction to ensure both speaker cables are routed in the same direction....ever tried to discern cable direction of poorly marked cable in bad lighting ?.
I don't think Naim claims cable directivity per se.
That said, I have encountered image skewing due to opposing speaker cable direction as per my turntable cable experience I detailed.
For this reason as a matter of course I always ensure that stereo cable pairs are routed in one direction.
Dan.
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Actually a bit more, but there is enough noise here.
For fun look up graphene and ballistic transport.
Ah, geeze..here we go again..
Ballistic transport...slamming into a target at the end of the micron channel after voltage gradient based acceleration.
There's almost as many inaccurate beliefs being pushed around with graphene as with superconductivity..
jn
Q is a charged term...
in any event how does charge carrier "velocity" change transmission line equations?
wouldn't seem to have 1st order effect on EM wave prop velocity
small, indirect effects through R loss or maybe internal L?
in any event how does charge carrier "velocity" change transmission line equations?
wouldn't seem to have 1st order effect on EM wave prop velocity
small, indirect effects through R loss or maybe internal L?
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Fun.
That's giving me nightmarish flashbacks of calculating this/single electron transport for single wall nanotubes my first year of grad school. It's just about exactly where I find my ability to do math falls apart. Flipping Euclidean spaces and such and looking at Fourier transformations of 3-D space was just a bridge too far for my brain to construct.
Man has got to know his limitations. 🙂
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