06-04-2011, 03:05 PM
(06-04-2011, 11:30 AM)beam me up schottky Wrote: Red heatsinks on the pass transistors !! The fins are red and the flat centre section where the transistors are mounted is natural aluminium.
Anyone seen red heatsinks before ? Any thoughts on why red ?
Yes, I have seen them before: they're TO-3 heatsinks, aren't they? I've also seen TO-5 heatsinks in that colour, light/bright blue, green and the common black. I've also seen red aluminium blocks for a pair of OC81 that could thus to be thermally joined as well as providing a heatsink. This colouring is brought about my an aluminium process called anodising (if my memory serves me well). This all started about the mid-'70s. I do believe that certain manufacturers simply used the colours to try to distinguish their particular products from the competition. Perhaps it was 'Redpoint' that went in for red; perhaps it was 'Redpoint' who started the whole colour fad off in the first place.
With passing of the years since, traditional black is now the colour - which makes engineering sense, since that is the colour that will give the most efficient transference of heat to the surrounding air.
Al.
