Insulation on LM3875's

[enzedone]

Is there a need to insulate these chips on the heatsinks if the heatsinks themselves will never come into contact with any other object that might conduct? I am using the T series..... Buying an insulation sheet just for two little chips is rather expensive..

 

[sofaspud]

No, you don't need the insulators.

 

[enzedone]

Sweet As

Cheers... I didn't think so but it's better to check

 

[Nuuk]

No, but be aware that you make it much more likely to cause an accidental short!

 

[peranders]

... and it may form an antenna but if the whole thing is located in a good (metal) box I think it's perfectly alright.

 

[enzedone]

Hmmmmmmm

O.k so it looks as though I'm just going to have to bite the bullet and buy an entire insulation sheet as my cabinets are not made from metal.....$50.00 for a 300ml x 30oml sheet, it doesn't come cheap. Boy so mush for trying to keep the cost down buy only buying the boards from Peter as opposed to the hole kit.

 

[Nordic]

Why not get the insulated version of the chips... might be a cheaper mod.

 

[enzedone]

Not possible

No thats a no go i'm affraid. I can only get the 'T' series here. I would have bought them if i could have, much easier to deal with. Thats the problem with living in a small country. Small market, bad service.....

 

[Nordic]

LOL, try living in Africa...

For National's distributors in NZ click here

 

[Nuuk]

O.k so it looks as though I'm just going to have to bite the bullet and buy an entire insulation sheet as my cabinets are not made from metal.....$50.00 for a 300ml x 30oml sheet, it doesn't come cheap. Boy so mush for trying to keep the cost down buy only buying the boards from Peter as opposed to the hole kit.

I don't know who your supplier is, but I would have thought that if they sell the full sheets of insulation, they would also do the 'standard' pads. It's the TO-220 type that you should ask for (about 11p each here in the UK).

 

[enzedone]

Cheers

I will contact those distributors. And also contact RSNew Zealand to see if they stock those pads..................cheers guys

 

[rampage101]

If you have access to any old pc power supplies you can scavenge a heap of little pads from them, I did and used 2 per chip, worked great.

 

[enzedone]

Cheers rampage

I gave that a go but they seemed to be quite broken down over time and just crumbled while trying to get them off. I thingk i will just order the set for the TO-220 that Nuuk suggested.


By the way, this is off the subject, but i have some 6mm perspex if anyone is interested. I managed to scab about $2000 worth of the stuff. They are in 250-300mm x 2m lengths. I have enough to build about 100 cases, so if anyone is interested. I could perhaps cut some down. They won't be perfect but i could cut a few pieces up and maybe send them off in the post if it's not too expensive...