"whisky-dave" wrote in message
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On Wednesday, 30 January 2019 04:16:40 UTC, Rod Speed wrote:
wrote in message
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On Tuesday, 29 January 2019 17:09:04 UTC, Dave Plowman (News) wrote:
In article ,
R D S wrote:
And why do similar rated ones differ so much in bulk? Is this just a
build quality issue?

Older ones will have a transformer. Newer ones a SMPS - smaller and
lighter.

All wallwarts use a transformer.

Not all of them do. Some of the lower
power ones just use a capacitor dropper.

How do they work then ?

The capacitance determines the AC current.

How do you know what voltage they produce

They are regulated after the cap.

and how will it convert the AC to DC.

There's rectification for that.

SMPSes just use a smaller one.

Wrong, as always.

They mostly use smaller transformers and
therefore lighter than the older sytle linear ones.

Duh, but not ALWAYS as the cat claimed.