"Graham." wrote in message
...
On Sun, 05 Jan 2014 19:33:38 +0000, Tim Watts
wrote:

On Sunday 05 January 2014 19:21 wrote in uk.d-i-y:

On Sunday, January 5, 2014 6:44:24 PM UTC, Tim Watts wrote:

Not understanding SMPSUs - do they provide complete magnetic
isolation
like
a simple transformer does?

Yes, assuming you mean ones with external power output

OK...


TRhe beuauty of a simple linera PSU for home build projects is it's
hard
to get it wrong, provided you keep the mains wiring nicely separated
from
the ELV side.

They're quick, easy & simple. SMPSUs arent.


I noticed lots of Christmas tree lights still come with conventional
transformers. Not much else though.

Only a transformer gives proper isolation from the mains for safety.
110V tools on building sites are powered via transformers.