Re: Instead scopes

On Mon, 02 Sep 2024 08:36:53 -0700, john larkin
<jlarkin_highland_tech> wrote:

On Sun, 01 Sep 2024 17:43:32 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
>

On Sun, 01 Sep 2024 13:17:03 -0700, john larkin
<jlarkin_highland_tech> wrote:
>

On Sun, 01 Sep 2024 15:53:46 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
>

On Sun, 1 Sep 2024 17:55:58 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>

john larkin <jlarkin_highland_tech> wrote:

On Sun, 1 Sep 2024 17:45:46 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
 

On 30/08/2024 2:21 am, Jan Panteltje wrote:

On a sunny day (Fri, 30 Aug 2024 00:43:39 +1000) it happened Bill Sloman
<bill.sloman@ieee.org> wrote in <vaq1f2$jdj$1@dont-email.me>:
 

It's lot easier and quicker to bread-board a circuit in LTSpice than it
is to wire up a test circuit, but what that means is that you need to
make fewer real circuits and they are a lot more likely to work when tested.
 
That, on it's own, is enough to explain why labs look different today
than they did in the dark ages.

 
All it explains is boeings falling apart and astronuts ending up stuck at the ISS
and no moonlanding from the US, not even a probe.
Slimulations are _not_ realty and never will be.

 
But they can capture useful parts of reality, if you know what you are
doing.
 
John Larkin's simulated inductors tend not to have any parallel capacitance.

 
The trick is to know when it matters. ESR and core loss are usually
more important.
 
I designed this surface-mount inductor for my Pockels Cell driver,
after several tries using commercial parts. They all smoked.
 
It's wound on a specially marked Sharpie pen that we have carefully
reserved.

>
It better have a regular calibration schedule, or your semiconductor
customers may give you the raised eyebrow.

>
Hmm.  To be overly serious:  With traceability to NIST (US) or NPL
(UK) or the like.
>
The trend in standards is to eliminate standards tied to a physical
object.
>
I have a Sharpie in hand.  The barrel that is not covered by the cap
is a truncated cone, being 11.0 mm at the blunt end and 12.32 mm near
the cap, 73 mm away.

>
Mine is pretty cylindrical for the length of the coil. I expect that
the operator's (ie, my)  applied tension affects the radius too.

>
Most likely.
>
>

That inductor sees 25 amps p-p, roughly a sawtooth, at 4 MHz. The
Coilcraft parts that I tried all smoked, I guess from skin effect and
proximity effect.
>

>
Actually, all that's needed is to specify an ideal geometric shape,
with tolerances, in the formal documentation. 
>
Joe Gwinn

>
I'll have someone start on a SolidWorks model.

>
I bet you need the standoff, so the lossy FR4 material isn't too
close.  That should be in the requirements as well.

>
That's another function of the gap-pad material. And the flattish part
of the circular solenoid windings make a big contact area into the
pads, for more heat transfer.

All good.  Needs to be in the drawing.

I'd specify the coil dimensions, not the mandrel dimensions, which may
be provided as a helpful suggestion only.

>
It would be cool is the bottom of the windings were actually flat, a
square or elliptical winding, for more heat transfer area.

.<https://www.mcmaster.com/products/~/d-profile-rotary-shafts-5/?s=shafts%2Fshafts-2%7E%2Frotary-shafts-5%2Fdiameter%7E12-mm>

This is what's easily available.  If you make your own mandrels, they
can be any shape.  Make sure that at least one end has a index slot or
radial hole, to make winding easier by allowing the clock angle of the
mandrel easily fixed.

Joe Gwinn