Clive wrote:
> A simple way to judge whether an appliance is wasting
> power or not on standby, is to feel how hot it's getting
> when left overnight - easier with a plug in power pack
> then a TV I must admit. The small solid state 'switch
> mode' plug in charger that came with my mobile 'phone
> is stone cold when left plugged in and on, yet the power
> supply to my external disk drive sits there roasting hot,
> even with the switch on the drive set to 'off', so I
> only plug it in when I need the external 'archive' drive.
> My old BT voyager 105 broadband modem was powered by the
> USB port, the new faster one they brought out is powered
> by a separate transformer, and both it and the transformer
> used to sit there 24/7 wasting energy. As I didn't notice
> much of an improvement in surfing speed, I went back to
> the old one.

I've been wondering about the possibilities of having a
low-voltage (probably 12v) "ring main" in addition to
the normal 230v. This would allow the many small power
conversion transformers common today to be replaced with
a single larger one.

In general transformer efficiency increases with size,
so this should save power. The low-voltage circuit could
also be used to supply low-voltage lighting circuits,
which again often have their own transformers. This will
be a particular win as low-voltage halogen is superceded
by low-voltage LED lighting ...