What to use for TO-220 isolating pad? - Page 2

MWP · 11th July 2003, 02:23 PM

You can use common TO3 insulators by cutting them in half.

millwood · 11th July 2003, 04:43 PM

Quote:

Originally posted by Netlist
There are silpads available in larger formats (100x100mm) which you can cut into the desired format.

does anyone know where I may be able to get those sheets in the US?

Thanks.

JOE DIRT® · 11th July 2003, 05:05 PM

silpad is very expensive.....I purchased a 12" wide roll for a production run and it was a 1000CAN.....we used a paper cutter to cut the required size which increased labour costs....I regret approving the decision now

DIRT®

dkemppai · 11th July 2003, 06:04 PM

Quote:

Originally posted by millwood

does anyone know where I may be able to get those sheets in the US?

Thanks.

Maybe Digikey... ...I order sillpads from there... ...but not sheets.

chris ma · 14th July 2003, 03:13 PM

Quote:

Originally posted by Peter Daniel
Plastc screw is OK when not much pressure is required (diodes), but on ICs and transistors, I'm using metal screw (non magnetic) and a plastic washer (I buy from Supremetronic).

Are those plastic washer are just normal flat ones, I am concern about the shaft of the screw may make contact with the inside surface of the heat sink thru hole. May be I have to use heat shrink on the screw first?

Peter Daniel · 14th July 2003, 03:14 PM

Those are washers designed for that purpose. They have additional lip, that prevents the screw from touching the case.

millwood · 14th July 2003, 03:19 PM

Quote:

Originally posted by chris ma
I am concern about the shaft of the screw may make contact with the inside surface of the heat sink thru hole.

Chris, like Peter said, those washers have extra-long "sleeves" that do precisely that: preventing the screw from touching the heatsink.

I have been using plastic tubing for that purpose as well.

AKSA · 15th July 2003, 12:14 AM

Since TO-220s normally run around 1W dissipation or thereabouts, I normally just use a simple bolt on heatsink like a THD6080 and don't even bother with insulation. This improves thermal coupling, and since the heatsink is small anyway you can usually tolerate it being at collector potential.

Cheers,

Hugh

Peter Daniel · 15th July 2003, 04:57 AM

The rest of a thread is here: http://www.diyaudio.com/forums/showt...608#post204608

14th July 2003, 03:14 PM	#16
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	Those are washers designed for that purpose. They have additional lip, that prevents the screw from touching the case. __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

15th July 2003, 12:14 AM	#18
AKSA diyAudio Member Join Date: Sep 2001 Location: Melbourne, Australia	Since TO-220s normally run around 1W dissipation or thereabouts, I normally just use a simple bolt on heatsink like a THD6080 and don't even bother with insulation. This improves thermal coupling, and since the heatsink is small anyway you can usually tolerate it being at collector potential. Cheers, Hugh __________________ Aspen Amplifiers P/L (Australia) www.aksaonline.com

15th July 2003, 04:57 AM	#19
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	The rest of a thread is here: http://www.diyaudio.com/forums/showt...608#post204608 __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

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11th July 2003, 02:23 PM	#11
MWP diyAudio Member Join Date: Oct 2002 Location: Adelaide, South Australia	You can use common TO3 insulators by cutting them in half.

11th July 2003, 05:05 PM	#13
JOE DIRT® diyAudio Member Join Date: Apr 2003 Location: Brantford, ON	silpad is very expensive.....I purchased a 12" wide roll for a production run and it was a 1000CAN.....we used a paper cutter to cut the required size which increased labour costs....I regret approving the decision now DIRT®

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