Heatsink, just don't drop it on concrete

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https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358

Damn, didn't realize they were making full heatsinks out of ceramic now.  
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the material  
(compared to AlN and Al).  Not spendy either.

Tim

--  
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
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Re: Heatsink, just don't drop it on concrete
On Mon, 17 Jun 2019 10:18:04 -0500, "Tim Williams"

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Sure, why not I guess...  

 They make power resistors out of the stuff



Re: Heatsink, just don't drop it on concrete
On 2019-06-17 08:18, Tim Williams wrote:
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95% Al2O3, so what's the other stuff in there? Doesn't look like the  
solder feet make up 5%.

And hey, they filed a patent for a laundry clip :-)

Come to think of it, one should be able to clip wet socks underneath  
there and then dry them.

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Regards, Joerg

http://www.analogconsultants.com/

Re: Heatsink, just don't drop it on concrete
On Monday, June 17, 2019 at 6:42:05 PM UTC-4, Joerg wrote:
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I think it is similar compounds with other metals than Aluminum.  I seem to recall this stuff is also very temperature stable, but has to be a lot more pure, <1% impurities, but I may be thinking of silica.  

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  Rick C.

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Re: Heatsink, just don't drop it on concrete
On 6/17/19 11:18 AM, Tim Williams wrote:
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Eight bucks for a 1x2 inch heatsink "isn't spendy"?  Aluminum ones run  
maybe 80 cents in onesies on Digikey.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs
Principal Consultant
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Re: Heatsink, just don't drop it on concrete
On 2019-06-17 16:29, Phil Hobbs wrote:
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But it does have its bling factor. Just imagine the unfettered flow of  
electrons in a class D stage, using space-age ceramic technology for the  
ultimate sound experience :-)

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Regards, Joerg

http://www.analogconsultants.com/

Re: Heatsink, just don't drop it on concrete
wrote:

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I'm skeptical about the cooling, but it would be nice for high
voltage.

Real bling and real cooling would be solid diamond.


--  

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement  

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Re: Heatsink, just don't drop it on concrete
Joerg wrote...
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 I struggle with the high heatsink capacitance of power
 transistor tabs. $7 is cheap at the price for s solution.
 Wanna make a 500V/us fast-slewing HV amplifier stage?
 Find a low-C power part, and a low-C heatsink.  :-)
 Read all about it in the soon-to-be-out AoE x-Chapters.


--  
 Thanks,
    - Win

Re: Heatsink, just don't drop it on concrete
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Y'know, I'll bet it's transparent to long IR as well.  Not that there's much  
to see on the metal backside of a transistor or what have you, but it may be  
useful sometimes.  A sil-pad would definitely be emissive, grease may be as  
well.

Tim

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Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
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Re: Heatsink, just don't drop it on concrete
On 6/17/19 11:16 PM, Tim Williams wrote:
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Nah, sapphire becomes opaque around 5 um, and polycrystalline alumina  
will be worse.

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: Heatsink, just don't drop it on concrete
On Wed, 19 Jun 2019 09:54:50 -0400, Phil Hobbs

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We sometimes want to thermal image a board in a box. If we remove the
top cover, the air flow all changes. FLIR sells a
thermally-transparent (looks like glass) window for some kilobucks
that we could install in the cover, or use to replace the cover.

We use the black plastic from the cheapest, thinnest garbage bags.


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: Heatsink, just don't drop it on concrete
On Wed, 19 Jun 2019 07:27:56 -0700, John Larkin wrote:

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Wouldn't clingfilm work?

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The from address exists but is mostly dumped,
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Re: Heatsink, just don't drop it on concrete
On Wed, 19 Jun 2019 17:50:11 +0100 (BST), "Rodney Pont"

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Some of it does. Again, the cheapest stuff is the thinnest.


--  

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement  

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Re: Heatsink, just don't drop it on concrete
On 6/19/19 10:27 AM, John Larkin wrote:
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Garbage bags are low-density polyethylene, which works pretty well in  
1-mil gauge.  I used that in my Footprints sensors to suppress  
convection near the sensor film.

HDPE is better if you can get it thin enough.

Cheers

Phil Hobbs



--  
Dr Philip C D Hobbs
Principal Consultant
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Re: Heatsink, just don't drop it on concrete
On Wednesday, June 19, 2019 at 8:32:42 PM UTC-4, Phil Hobbs wrote:
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there's
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ut

ive,
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Why, what is better about it?  HDPE is milk jugs and kayaks.  Both pretty t
hick.  Where do you find it thin?  

--  

  Rick C.

  +++ Get 1,000 miles of free Supercharging
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Re: Heatsink, just don't drop it on concrete
On 6/19/19 10:32 PM, Rick C wrote:
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You could melt a bleach bottle and smear it out into a thin layer.  
Commercially? Dunno.

Cheers

Phil Hobbs


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Dr Philip C D Hobbs
Principal Consultant
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Re: Heatsink, just don't drop it on concrete
Bottom posting. (Google here)  

No insulator. Could glue a chip to it and have some advantages with that. Power transistor cases, much better than plastic and if you can get the silicon to stick to it you have a really good package.  

In my opinion, ceramic is a bit too hard to machine for use as heat sinks per se. This stuff about near has to be molded to its shape the first time. With holes.  

I wonder how brittle it really is. (was mentioned "drop it") Maybe I'll get one and find out. I do have a cement floor.  

If I remember I might, got other things to do right now.  

Re: Heatsink, just don't drop it on concrete
On Wed, 19 Jun 2019 22:13:18 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

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I sure hope that the semi contact area is ground flat. Moulded ceramic
is usually rough, and roughness wrecks thermal conductivity. But I
guess that's not so important for a small heat sink.


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: Heatsink, just don't drop it on concrete
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If it's HIP like I suspect, the surface will be not only mirror finish, but  
so smooth that you have little hope of getting a strong epoxy bond, if you  
wished to glue to it.

Tim

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Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
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Re: Heatsink, just don't drop it on concrete

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  His claim is false.  A ROUGH surface degrades an interface.  It  
would have to be very rough though.  The smoothness a cast or  
moulded ceramic face has is far too fine grained a surface profile  
for it to degrade thermal flow.  And it will also allow adhesive  
attachment a bit more.

  And the other problem mirror finish has (for epoxy attachment) is  
that if your epoxy detaches, it is as if it is not even attached at  
all.  Smoke ensues.

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