In article ,
The Medway Handyman wrote:
Just for guidance SMPS are quite light and usually shaped so they'll
fit through the downlighter mounting hole. A true transformer will be
much heavier - and likely larger too. Most these days are SMPS.

Thanks Dave (& John).

That makes perfect sense, I used the word 'transfomer' almost in a
generic way. Seems that SMPS are described as transformers even by TLC

http://www.tlc-direct.co.uk/Main_Ind...ers/index.html

They call them electronic transformers and the 'proper' transformers
toroidal - which is actually a type of transformer. I've seen low voltage
lighting true transformers which weren't toroidal.

But it makes some sense to call them all transformers because they do the
same job. And most won't be interested in any differences internally.

Are these really SMPS's?

The electronic ones, yes.

To further my education :-) how does an SMPS work in simple terms? I
understand how a transformer works more or less, how does an SMPS
achieve a similar thing?

Like for like, transformers gets smaller as the frequency increases. So
an SMPS converts the 50Hz mains frequency to something like 30,000 Hz. So
a much smaller and cheaper transformer can be used.

What about wall warts? Is a Nokia phone charger an SMPS?

Most are these days. When you make things by the million the material
costs are important and the saving in expensive copper for the windings
etc can easily exceed the complexity of making the thing. As well as
making it smaller for a given output. It's also simple to make an SMPS
that will work with virtually any input voltage and give a constant output
- not so with a normal one.

--
*Is there another word for synonym?

Dave Plowman London SW
To e-mail, change noise into sound.