Nifty heat sink...

[Jim MacArthur]

I\'ve been annoyed by the lack of imagination in heat sink extrusions. Also the pandemic. But this extrusion is pretty clever:

https://www.ohmite.com/assets/docs/sink_c40.pdf?r=false

Perfect for spot-cooling on a PCB. When paired up, you can bolt a 40mm fan right onto the end. If you forego the clip, you can bolt four TO-220 parts to each heat sink. Here\'s a pic of four heat sinks in action:

https://wiki.harvard.edu/confluence/display/ESHOP/LT1210X8

With a setup like this, you can position either end of the wind tunnel against a hole in the enclosure.

-Jim MacA.

 

[Steve Wilson]

Jim MacArthur <jimbmacarthur@gmail.com> wrote:

I\'ve been annoyed by the lack of imagination in heat sink extrusions.
Also the pandemic. But this extrusion is pretty clever:

https://www.ohmite.com/assets/docs/sink_c40.pdf?r=false

Perfect for spot-cooling on a PCB. When paired up, you can bolt a
40mm fan right onto the end. If you forego the clip, you can bolt
four TO-220 parts to each heat sink. Here\'s a pic of four heat sinks
in action:

https://wiki.harvard.edu/confluence/display/ESHOP/LT1210X8

With a setup like this, you can position either end of the wind tunnel
against a hole in the enclosure.

-Jim MacA.

The fans will eventually collect lint and block the airflow. See

Bring out your dead: Reg readers reveal filthy, filthy PCs:

https://www.theregister.com/Print/2009/11/06/dirtiest_pc/
https://www.theregister.com/2009/11/13/ventblockers/
https://www.theregister.com/2010/11/18/ventblockers_2/
https://www.theregister.com/2013/02/01/ventblockers_3/

Eliminate the fans. Go class D:

What are the Different Types of Audio Amplifier Classes?

https://www.audioholics.com/audio-amplifier/amplifier-classes

and

Amplifier Classes from A to H

https://circuitcellar.com/cc-blog/amplifier-classes-from-a-to-h/


--
Science teaches us to trust. - sw

 

[server]

On Mon, 7 Dec 2020 14:17:38 -0800 (PST), Jim MacArthur
<jimbmacarthur@gmail.com> wrote:

I\'ve been annoyed by the lack of imagination in heat sink extrusions. Also the pandemic. But this extrusion is pretty clever:

https://www.ohmite.com/assets/docs/sink_c40.pdf?r=false

Perfect for spot-cooling on a PCB. When paired up, you can bolt a 40mm fan right onto the end. If you forego the clip, you can bolt four TO-220 parts to each heat sink. Here\'s a pic of four heat sinks in action:

https://wiki.harvard.edu/confluence/display/ESHOP/LT1210X8

With a setup like this, you can position either end of the wind tunnel against a hole in the enclosure.

-Jim MacA.

I considered those recently, but they looked mechanically fragile on a
PC board.

I went with individual heat sinks, which we had in stock anyhow.

https://www.dropbox.com/s/sry2fjqpvvhlx5w/535-0009.jpg?raw=1

https://www.dropbox.com/s/tp6g1prykyua301/525-0009_Test.jpg?raw=1

which have the advantage of not needing insulators.

These will go on a PCB with a fan mounted on the board too, blowing
directly on four big fets in an h-bridge.






--

John Larkin Highland Technology, Inc

The best designs are necessarily accidental.

 

[Jim MacArthur]

I considered those recently, but they looked mechanically fragile on a
PC board.

I went with individual heat sinks, which we had in stock anyhow.

https://www.dropbox.com/s/sry2fjqpvvhlx5w/535-0009.jpg?raw=1

https://www.dropbox.com/s/tp6g1prykyua301/525-0009_Test.jpg?raw=1

which have the advantage of not needing insulators.

These will go on a PCB with a fan mounted on the board too, blowing
directly on four big fets in an h-bridge.

John, your point about mechanical stability is well taken. I would definitely hesitate to use these in singles. In pairs, with a fan bolted on, they\'re solid as a rock, but on my board, the two heatsinks without a fan are pretty floppy. I think I\'ll bolt a fan guard onto those two, to stabilize them. This application put an emphasis on compactness and the ability to duct the heat away from the experiment, so this heatsink system is a natural.

Steve, this board is four amplifiers, bridge driven 40Vpp at 1A, DC to 10 MHz, so class D is not an option.

-Jim

 

[Mike Coon]

In article <XnsAC8CC613114ACidtokenpost@69.16.179.20>, spam@me.com
says...

--
Science teaches us to trust. - sw

Are you aware of the The Royal Society of London - \"The story of the
Royal Society is the story of modern science\"?

Their web site says:

The Royal Society\'s motto \'Nullius in verba\' is taken to mean \'take
nobody\'s word for it\'. It is an expression of the determination of
Fellows to withstand the domination of authority and to verify all
statements by an appeal to facts determined by experiment.

They plainly think \"trust\" has nothing to do with it!

 

[John Larkin]

On Tue, 8 Dec 2020 04:10:21 -0800 (PST), Jim MacArthur
<jimbmacarthur@gmail.com> wrote:

I considered those recently, but they looked mechanically fragile on a
PC board.

I went with individual heat sinks, which we had in stock anyhow.

https://www.dropbox.com/s/sry2fjqpvvhlx5w/535-0009.jpg?raw=1

https://www.dropbox.com/s/tp6g1prykyua301/525-0009_Test.jpg?raw=1

which have the advantage of not needing insulators.

These will go on a PCB with a fan mounted on the board too, blowing
directly on four big fets in an h-bridge.

John, your point about mechanical stability is well taken. I would definitely hesitate to use these in singles. In pairs, with a fan bolted on, they\'re solid as a rock, but on my board, the two heatsinks without a fan are pretty floppy. I think I\'ll bolt a fan guard onto those two, to stabilize them. This application put an emphasis on compactness and the ability to duct the heat away from the experiment, so this heatsink system is a natural.

Steve, this board is four amplifiers, bridge driven 40Vpp at 1A, DC to 10 MHz, so class D is not an option.

-Jim

Just got a solder-sample board and checked the heat sink mounting.

https://www.dropbox.com/s/6m8h3g2vvc4pv4n/P902B_heat_sink.jpg?raw=1

Looks good, nice and rigid. There will be four of them, on the bottom
side, with a fan on the board just to the right.