Electrical Engineering

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Asmyldof

09:23

@JonRB Isn't 3313 much better than multiple layers of 1080 or similar?

JonRB

10:09

@Asmyldof the reason for double-prepreg is to mitigate voids in the weave IF different layers are going to support > 270V.

if you cannot ensure voids it is better to deal with it via statistics as in... what is the probability that two void in two parts of prepreg align to then compromise the voltage withstand

Asmyldof

@JonRB Ah, that kind of voiding. You never told me what you were doing

JonRB

true :)

"high voltage" and "high current" on a PCB can be annoying

Asmyldof

Seems to be a chatroom phenomenon

I know

Done it often enough

JonRB

Basically I am re-doing a 5kVA inverter I designed a number of years ago ( fluidmotion.no-ip.org/files/exciter-populated.JPG )

Asmyldof

Well... "high" voltage

I've also worked a tiny bit with 25kV, but never both paths on one PCB ;-)

JonRB

10:13

by "high" it isn't what I would class as high ... this is only 800V max working voltage

BUT the annoyance is altitude

20,000ft is ROYALLY annoying w.r.t. Paschen's law

Asmyldof

Pressurised pure nitrogen packaging. Obviously

Or maybe some even more suitable gas. Never really thought about gasses in that sense

JonRB

HumiSeal

it scraps the cards BUT totally seals it

Asmyldof

Sounds more like a diaper for aquatic animals

JonRB

no rework capability

Asmyldof

Yeah, my stuff usually never goes outside of the 1km above sea ranges

Normal conformal coatings is pretty much where my packing experience ends.

Well and some special ones I'm not allowed to talk about

JonRB

10:17

so I am back to design to correct some endemic design habits that have crept in (only so much that can be done as a tech manager over a number of years )

Fo some reason a "reference design" that people constantly use for RTD is piss-poor

"but this was used on the last program" SO FIX IT!!!!

its simpler to carry on and let the inertia of process push it along rather than improving a design.

when an RTD circuit is sensitive to 60us burst of noise (shock horror... poor layout and motordrives) and the 150A overcurrent protecdtion has a persistency of 150us, you know there is an issue

Asmyldof

Hah.

I know those kinds of symptoms well too.

Half the times I used to get called in for short projects a few years ago was because someone finally convinced a manager that it needed to be done and that if nobody internal had time, they should just get someone else to fix it

Seeing more the positive side of that story in most cases, luckily

JonRB

yup. once it is done it is worth it... it just takes a lot to change a culture.

Asmyldof

10:37

Sometimes I'm sad I'm never there to help with that, many times I'm happy I'm not the one faced with that struggle

PlasmaHH

you could offer best effort contracts where when its too much you can sit in the corner, drink a beer and make witty comments.

Asmyldof

Oh, no, I always complete the work. Just sometimes after initial investigation the quote for it is so high they decide not to let me do it.

2 hours later…

Asmyldof

13:13

@JonRB How impactful does aerospace consider the effect of altitude to traces buried inside an inner PCB layer?

Marla

@Asmyldof You should post that as a question on main site. I never thought of possible delaminating at high altitude.

Asmyldof

Was just curious and since Jon works on that....

Also I'm super lazy right now

2 hours later…

PlasmaHH

15:00

@Marla maybe not altitude, but certainly on impact

2 hours later…

Asmyldof

16:38

I find it very hard not to comment in a very mean tone about arduino and crap under this, admittedly fair, point:

Q: This question should not have been migrated!

I don't know why but sometimes I have seen question like this being migrated the Arduino because they have the Arduino tag and has nothing to do it. This is actually a very poor question and should have been closed. I am not trying to pull a debate with the moderator but I feel this site should s...

discussion

Branden Boucher

16:52

@Asmyldof meaning you agree with the author that his question had nothing to do with arduino?

Asmyldof

@BrandenBoucher That as it is, it should be closed. Can't just throw all your garbage onto your neighbour's lawn. Even if all his grass is already withered away

Branden Boucher

agreed!

Asmyldof

17:08

I'm 100% certain I have seen this question asked literally the exact same about a week ago:

-1

Q: What Prevents load voltage from Flowing into Vsupply in this circuit?

Here, U1 is an optocoupler called TLP250. It is powered by Vsupply which is 12 V. V2 is the load voltage and it is at 24V. But it can be as much as 200V. My question is, that since both Vsupply and V2 share the same ground, what prevents current from V2 from flowing into the Vsupply ground whe...

mosfet switches mosfet-driver powermosfet

Branden Boucher

17:53

general question for anyone who is just bored enough for a possible convo. I remember the learning curve when getting into AVR MCUs. Looking to get into Microchip MCUs and wondering if anyone has some good suggestions (resources, tutorials, ...)

PlasmaHH

18:18

So the trashpile complains getting trash thrown over...

@Asmyldof see the other question that user posted

Asmyldof

Too lazy

Watching Cartoon President

PlasmaHH

Same schematic

@Asmyldof white house live stream?

Dinner time

Asmyldof

@PlasmaHH No, not just same schematic. Exactly the same question

@PlasmaHH Very close. en.wikipedia.org/wiki/Our_Cartoon_President

AlmostDone

19:22

@BrandenBoucher Microchip web site has a large base of applications and FAQs that go back many years, including a forum where questions can be asked similar to stackexchange. I've used toolsets from others but found the MPLAB-X and their pro C-compiler, along with their ICE pod, to suit my needs best.

Branden Boucher

Ah. @AlmostDone, thank. Beat me to my next question even which was, what programmer to use.

3 hours later…

AlmostDone

22:53

@BrandenBoucher @BrandenBoucher Programmer included in the RealICE. Prior to that, I tried the mikroProg pod, but the debugger that goes with it wouldn't allow me to step into a call and see vars in a structure. RealICE didn't have that problem. Just recently started using the TagConnect programming cable for programming. The footprint is much smaller than a 10P header or the RJ11.

Branden Boucher

That is very helpful! Thanks!

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