USB chargers.
Over the last year or so I have acquired various devices that come with a USB charger.
Not all have the same final termination, but most have a separate cable that plugs into a UK three-pin plug (that is, presumably, a transformer of sorts).
Is it safe to swap cables from 'transformer' to transformer (ie does a full-size USB socket have identical characteristics)?
What about using USB sockets in cars (and, now, buses)?