** What Rod Elliot wrote above is **completely correct** - backed up by actual measurements and published data you can find in the supplied links.
Time the posturing pommy Wanker learned to bloody read !!!!
** Shame how external, transformer based supplies, range from 1 watt up to 100 watts or more.** Shame how this makes them economical to produce and have far better voltage regulation than otherwise. ** There is NO problem.
The whole idea of banning them is utterly STUPID !!.
** Then the core size must be increased quite dramatically to achieve the same VAs and regulation factors.Then the core and copper losses increase again.
** Rod's comment was about " presently available " external transformer based supplies - virtually all of which are E-core types.Such designs become inefficient unless operated near the core's saturation limit.
The new rules require external PSUs to be unusually efficient, as well as have very low off load power loss.
Taken together ( which Win has stupidly failed to do) this means that E- cores are basically ruled out of the game.
Even the majority of *presently available* SMPS are ruled out of the game !!!
Only new generation SMPS ( which basically cease to switch with no load) will pass.
As I have noted here already - it is possible that in some VA ratings ( between say 7VA and 50 VA ) an R-Core design would make the grade PLUS be able to meet Class 2 insulation requirements - which is also essential.
None on the horizon, anywhere I can see.
...... Phil