Battery charger with surge suppressor?

[bobtrips]

On a travel forum that I frequent someone stated that all consumer multi-voltage devices such as battery chargers have built-in surge suppressors.

Can anyone confirm/deny that?

Any links with detailed information?

If some, not all, is there an easy way to tell?

 

[rexter]

Since the good Varistors becomes costlier as it's grow in size, with surge suppressors the transformer would have been more expensive than a regular unit.

My opinion to this is that small universal transformer may not have capability to suppress higher current.

Larger unit may have it but bear minimum, since they have to perform stable output 'till 265V. Which from 330 Volts is "suppressed voltage rating" of UL listing if I'm not mistaken.

If I need correcting please feel free to do so, Since I only sum-up my conclusion base on very limited knowledge about power supply.

Sorry I don't have any link to back that up.