USB outlets, phone chargers and vampire appliances

[Jacob Jones]

We aren't discussing just USB sockets.

[The Natural Philosopher]

Yes.

Capacitor droppers are not switched mode power supplies and all switched mode power supplies *that are isolated from the mains* MUST have a transformer.

I am fairly sure that no wall wart is allowed that is NOT isolated from the mains Only built in in stuff like LED lamps is 'live' at the lower voltages

[Jacob Jones]

Not just led lamps, led strips and other low powered stuff that plugs directly into the mains too. Most obviously with double insulated stuff.

[newshound]

I don't believe the 23% figure from the Centrica report. I've emailed "More or less" about it.

[Max Demian]

Well mains LEDs aren't going to have a standby mode, are they?

Most devices have bits that can be touched, like earphone sockets, and so require galvanic isolation.

I don't suppose microwave ovens or washing machines draw much power when they aren't working.

[Peter Able]

If you are searching for "vampire appliances" switch off appliances which have a lit display 24/7, such as Microwave Ovens.

PA

[Andrew]

Also, if removed from the 3-pin socket, it uses very little power, i.e. Zero :-)

[David Wade]

Only the really old ones are "a transformer". Anything new will be a switched mode PSU which adjusts its consumption from the mains to match the load.

Well they waste some. The 13amp sockets with USB will tell you how much they waste. So for example BG quote less than 50mW

just to put that in perspective its about 1 KWH every 2 years. Even after the latest price rises that is less than 30p every two years.

Poor design. Old design with a real transformer. Actually working.

Dave

[David Wade]

One other point no one has mentioned is that in the winter, any power used is radiated as heat , you said some get warm, so if you have for example, radiators with thermostatic valves, they will turn off sooner because the hat from the USB sockets goes into the room.

I doubt its noticeable, but when I changed the halogens in my kitchen for LEDs my wife started complaining it was cold and started turning on the fan heater in the plinths to compensate so I lost out...

Dave

[Dave Plowman (News]

Quite. But doesn't suit the popular press, where all heat generated by standby appliances is wasted.

[Martin Brown]

My new Smartmeter display mains PSU looks like it might well be a capacitive dropper probably with a choke in series to stop spikes.

It is USB-C connector shrouded by an additional male plastic hood so that the metal parts are out of reach and so that it can only be plugged into their display which has a matching female receptacle for the (polarised) chunky plastic shield.

In ASCII art:

O##### ==# O#####

Where # represents a hefty plastic 3mm thick shroud around the metal parts of the USB-C plug shown as ==. It claims to be CE approved...

I haven't dismantled it to see if my suspicions are correct.

[Animal]

exactly. No need to waste time on mr rodplonker

[Animal]

SMPSUs driving touchable loads all use a transformer for isolation. The prime difference is that they run them at high frequency, it's more efficient.