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Bottlehead Kits => Crack => Topic started by: EarWorm on July 04, 2014, 04:47:57 PM

Title: Some Schottky Diode Questions.
Post by: EarWorm on July 04, 2014, 04:47:57 PM

I noticed that some folks upgrade to Schottky's in the crack and I am looking for any hints and tips, photos, on installing them, which ones to purchase, and how much trouble they are to install.

Is the Schottky in this link that will suffice?  I'm not sure which one.  The 1A 600V seems to fit the bill but I'm not sure.  Is there an advantage to using one with higher current ratings?
http://www.partsconnexion.com/rectifier_diode_cree.html


Are they easily damaged while installing?  Should I order a few extra? ::)

Thanks all.

Title: Re: Some Schottky Diode Questions.
Post by: Paul Birkeland on July 04, 2014, 08:10:03 PM

The 1A 600V Cree will work in the Crack circuit.

If you can figure out how to mount them safely in a Crack, be sure to post a photo! (Those metal tabs are a PITA without some kind of PC board to hold them)

Title: Re: Some Schottky Diode Questions.
Post by: JamieMcC on July 04, 2014, 09:46:41 PM

I have some Crees on hand as well but as yet have not found a eloquent enough method of implementing them the closest I have got is considering using one of these pcb boards mounting it separately with lead outs to the Crack terminals. I decided in the end that perhaps it would be best to leave well enough alone and save them for another build as it would be easier to implement from a fresh than retro fitting.


(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi.ebayimg.com%2F00%2Fs%2FNDM2WDY1MA%3D%3D%2Fz%2FRjAAAOxyDo1TjobO%2F%24_12.JPG&hash=e6607456570db38f626c77da53457fe7f5400409)

Title: Re: Some Schottky Diode Questions.
Post by: EarWorm on July 04, 2014, 10:48:05 PM

What about something like ?
http://www.partsconnexion.com/product26996.html

Title: Re: Some Schottky Diode Questions.
Post by: Paul Birkeland on July 05, 2014, 07:54:29 AM

Yeah, it's tough.  A PC board will work, but then you have to consider how you're going to keep that PC board stable, as you don't want it twisting around and allowing those little metal tabs to touch other parts (especially if you have added chokes or big caps). 

Title: Re: Some Schottky Diode Questions.
Post by: JamieMcC on July 05, 2014, 08:15:45 AM

Paul, totally agree it would need properly mounting on stand offs or a non conductive board fixed to the top plate, one of the ideas I was thinking of which might offer a safe solution was after mounting them on the pcb would be then potting them. I and had been meaning to ask if such a method might be a suitable.  Possibly in a small tube or box and then filling it with a resin or high temperature hot glue to cover the Crees's and tabs completely.

Title: Re: Some Schottky Diode Questions.
Post by: Paul Birkeland on July 05, 2014, 08:23:28 AM

I suspect you could get away with potting.

You could also use some short wood screws to attach two of the tabs to the wood base.

Title: Re: Some Schottky Diode Questions.
Post by: mcandmar on July 05, 2014, 08:59:24 AM

PCB boards are a good solution, once they are well soldered on you could use these http://www.ebay.co.uk/itm/TO-220-Transistor-Silicone-Rubber-Cap-Insulator-x-10-/150665380021?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item23145b40b5 (http://www.ebay.co.uk/itm/TO-220-Transistor-Silicone-Rubber-Cap-Insulator-x-10-/150665380021?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item23145b40b5) for a bit of insurance.   Of if your cheap just a length of heat shrink around them.

Title: Re: Some Schottky Diode Questions.
Post by: Doc B. on July 05, 2014, 09:08:54 AM

Another alternative is to build a Mainline, that already has Cree Schottkys. Don't get me wrong, I totally understand the need to mod stuff. Just offering another option.

Title: Re: Some Schottky Diode Questions.
Post by: EarWorm on July 05, 2014, 01:17:42 PM

Mainline!   Perhaps that's next ;D

Those insulator caps are interesting.  Do the Schottkys emit much heat?  Would they be OK covered like the? 

As far as potting the Schottkys what potting material might be used?  Would there be an enclosure?

I'm OCD interested in potting the two Hammond 159M chokes I have on a larger chassis and mounting them up top.

Anyone have experience potting?   I was reading over on Jimmy,s Junkyard a choke he potted and for no other reason than OCD now i'm interested in it.

He did a nice looking Lundahl which for me looks too nice to hide away.
http://jimmyauw.com/2012/05/14/potting-the-lundahl-choke-part-1/

Title: Re: Some Schottky Diode Questions.
Post by: Paul Birkeland on July 06, 2014, 02:25:52 PM

I have potted a few things over the years.  If you're going to pot a choke that is 5H at 90mA, you might only want to do so if you're running it way under 90mA, as the resin encasement will interfere with the choke's ability to cool itself.

-PB

Title: Re: Some Schottky Diode Questions.
Post by: EarWorm on July 06, 2014, 03:11:27 PM

Potting the chokes are an interesting idea but dressing them up for display may be more fun.

But what about potting those Schottky's after they have been assembled on one of the fore mentioned  PC boards?   Might they be potted and still perform without hindrance? 
 It looks like another fun idea.

Title: Re: Some Schottky Diode Questions.
Post by: 2wo on July 06, 2014, 06:26:56 PM

In this case, The diodes are not dissipating much heat, so you can pot them if you want.

Me, I just cut a hunk of heat shrink to cover the whole device and call it done...John 

Title: Re: Some Schottky Diode Questions.
Post by: EarWorm on July 07, 2014, 11:32:27 AM

Good Lord!
http://krayden.com/pdf/lord_Potting_Encapsulation_2012.pdf

Title: Re: Some Schottky Diode Questions.
Post by: JamieMcC on July 07, 2014, 01:08:22 PM

My only experience with potting so far has been limited to Shrimp!   :D