PSU info please

[#1]

I have a shortwave radio, that is powered by a 13.5v regulated power supply unit. It has an illuminated rocker switch on it, to show it is sending power to the radio  when illuminated. It is permanently plugged into an unswitched wall socket.
When the switch is on, and illuminated, on the psu, BUT the radio is not switched on is the PSU using electricity?

[#2]

Inevitably. How much will depend on its detailed design.

[#3]

Yes but not much I believe
The reason I suggest that is that the transformer/rectifier part will still be working even though there is no final output
You can always get an indication by seeing how warm it gets when switched on when the radio isn't

[#4]

Hi Jim
Well, it has been "on" for most of the day, and is "only just" a bit warm... so I don`t think it would be using much....  was just a query, as I forget to switch it off when I have finished using the radio...
it is similar to this one http://www.maplin.co.uk/p/maplin-41w-dc-fixed-voltage-bench-power-supply-xm20w
and the radio only draws about 2 watts when running.....

[#5]

On the plate you might find a rating that says "No Load Wattage" or "Quiescent Consumption".
To nail it though, you'll need a power monitoring plug, -
Like this one at Maplin http://www.maplin.co.uk/p/15a-plug-in-energy-saving-monitor-l61aq ; - or check out eBay.
Maybe you can get a cheap/free one through your energy supplier?
Sometimes these monitors show real surprises; our Epson printer when in 'standby/off' was drawing the same energy as a 40W lightbulb. It's now gone to Silicon Hell - express.

[#6]

Quote from: Thunderclap

our Epson printer when in 'standby/off' was drawing the same energy as a 40W lightbulb. It's now gone to Silicon Hell - express.

Just unplug the blighter!!!
It'll take a good while to recoup the cost of a new printer in electricity savings but they don't need to be plugged in all the time anyway.  PULL THE FLIPPING PLUG!  Even accounting for the calories used in walking to the printer and unplugging it and the price of staple foods and the body's relatively poor energy conversion efficiency this seems an obvious solution to me. 

[#7]

That Epson was a piece of sCrap anyway. Many people don't realise how much power their scanner/printer thing is consuming. You're right turn it off. Anyway, elecronic devices are made for the American market where every kilowatt hour of electricty comes with a free bucket of regular Pepsi and fries.