PSU > How Much Power!?i

Ice Rich · 24 Apr 2008 at 08:48

Hi all,

Am I right in saying that as long a PSU is relatively modern, it will only take/use the amount of power needed? For example, a 1000w PSU would use no more then a 200w PSU as long as the usage is the same?

Ice Rich · 24 Apr 2008 at 13:39

Green-Peace said:
Pretty much ALL PSU's will only supply the current that the load demands/requires.
As far as efficiency comes into it then your talking about power factor, inductive and capacitive reactance ..etc ..etc.
But yes modern PSU's are more efficient as they have active power factor correction which means it can alter the value of capacitor used to correct the power factor as the inductance will alter depending on the amount of current being drawn.

Thanks for that

Whilst on topic, im using an extension lead (not for the extension but to give me more inputs), is it worth spending any extra on a quality extension unit? This may sound silly but could it handle the efficiency of electricity better?.

Ice Rich · 4 May 2008 at 09:29

Sorry to bring up this post again but I've just ordered a 'Belkin Gold' 7way plug extension lead. It seems very good quality but is it ok to use all 7 of the outputs at same time? I.e speakers, pc, 360?

Ice Rich · 4 May 2008 at 10:57

semi-pro waster said:
You've still got the limitation of the fuse in the plug at the end of the extension lead (i.e. up to 13A) but if all your devices use less than that it should be safe.

I'll be honest and say my knowledge of electricity is minimal. So are you saying 13A is the maximum fuse you can get, and that all the devices on the extension (when in use), should not exceed 13?

Ice Rich · 4 May 2008 at 11:21

semi-pro waster said:
13A is the largest fuse I've seen, certainly for domestic use so yes, when in use you shouldn't exceed 13A or you'll have problems.

Thanks, So a typical 'large' device e.g PC, XBOX, coffee machine would be around 3A?

Ice Rich · 4 May 2008 at 11:33

semi-pro waster said:
Should be that or less but most will have a 3A fuse in them I think so it ought to be fine.

Do you know if a fuse is like a PSU i,e it only takes the power it needs? Or is it always working at 3a? I feel a bit stupid for asking these questions as im sure its stuff all you guys know, but i really have not got a clue with electricity. Thanks

Ice Rich · 4 May 2008 at 11:42

semi-pro waster said:
I'm not an electrical expert either but a fuse simply acts as a cut-off switch, when 3A (or whatever) is exceeded then the fuse blows and stops the current flowing because the circuit is broken. All that will be passed through a fuse is what is necessary plus a miniscule amount which will be lost due to the inevitable resistance of the wire itself (I think).

I see, thanks. Is there a guide between the number of amps to use for a certain amount of wattage or are they not really connected? I.e would a 300w need mores amps then 600w?

Ice Rich · 4 May 2008 at 12:14

A huge thanks for your help guys, made it much clearer for me especially with the formula to work out watts/amps. Rich

Ice Rich · 4 May 2008 at 12:23

thegoonden said:
That's one scary cooker!

We used to run out stage rig, some 30+ devices, from a single plug, and no problems at all, as total consumption was less that 1000W.

You've confused me now

I thought, based on the posts above. You could go upto 3000w based on a 13amp fuse?

Ice Rich · 4 May 2008 at 12:40

thegoonden said:
You can, hence 1000W is fine.

Sorry, understand now. I thought you were saying have as many devices as you want but dont go past 1000w