On Monday 06 January 2014 09:43 Dave Liquorice wrote in uk.d-i-y:

On Mon, 6 Jan 2014 09:14:23 -0000, Brian Gaff wrote:

I really think the main reason most manufacturers went to smpsus was
weight in transit from the far east!

I don't think you pay by weight (within limits) for containerised
surface shipping, you pay by the container, which you stuff with as
much as will fit... Saw on the telly (so it must be true) that a 20'
container from the Far East to Europe costs about £1500.

wow - cannot believe it is so cheap! I guess you add local transport (lorry)
to that too.

Think how
many wall warts you could get in a 20' container, shipping costs are
minimal...

4x4x3" box - OK... That's about 50,000 PUS allowing 10% or so for external
boxing/packaging.

So 2.8p per unit. Blimey. No wonder ebay can sell stuff so cheap!

The reason is that you can make a SMPSU that'll work from 60 V to 250
V AC or DC. So one single power unit will work anywhere in the world.
All you need to do is provide a selection of clip-on country specific
adapters.

I do wonder how "green", cradle to grave, a complex SMPSU is compared
to a simple linear supply. The SMPSU might be more effcient in use
but will that energy saving be more than the extra energy it took to
make?

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