Well, I've been testing out all sorts of electric and electronic gear to 
find out what actually uses the most power. The results are very 
surprising...

The most thirsty device I've found so far is... the kettle. It uses in 
excess of 3,000 W for the entire duration that you try to boil water 
with it. On the other hand, something like the washing machine uses a 
tiny fraction of that, even when it's on its highest spin cycle. (Uses 
only 600 W. Actually uses 700 W while it spins up, but then drops to 600.)

I haven't tested out the TV yet, but of all the stuff I have tested, it 
seems that any device that performs any kind of *heating* instantly uses 
many times more power than anything else. I emphasize: MANY TIMES more 
power. Not 20% more, not 50% more, but nearer to 1000% more! Heck, even 
the vacuum cleaner (surely a high power device) in fact uses a fraction 
of the power that the toaster does!

Can anybody suggest why this might be? I mean, huge powerful electric 
motors use a fair bit of power, but it's almost insignificant compared 
to heating devices. Why does heating things require so much power?

Also, I notice that my PC uses about 10x as much power as my laptop. 
There are two possible explanations for this:

1. My PC is (or recently was) leading edge, whereas my laptop was pretty 
much old hat even when it was purchased.

2. It's a laptop. It's designed to use less power.

PS. We have *another* Intel Core 2 Duo laptop at work. And just like the 
first one, it seems to be utterly impossible to make it heat up, no 
matter how much number chrunching I throw at it. How do they manage that?

-- 
http://blog.orphi.me.uk/

Post a reply to this message

No answer (sorry), but two questions :

- What device do you use to mesure power ? Is it expensive ?

- Have you tried to mesure the power used by electronic devices (TV, 
HiFi, etc.) when they are on standby ? I find it difficult to get a 
estimation for this, and it seems to vary greatly even among similar 
devices ?


Thibaut


> Well, I've been testing out all sorts of electric and electronic gear to 
> find out what actually uses the most power. The results are very 
> surprising...
> 
> The most thirsty device I've found so far is... the kettle. It uses in 
> excess of 3,000 W for the entire duration that you try to boil water 
> with it. On the other hand, something like the washing machine uses a 
> tiny fraction of that, even when it's on its highest spin cycle. (Uses 
> only 600 W. Actually uses 700 W while it spins up, but then drops to 600.)
> 
> I haven't tested out the TV yet, but of all the stuff I have tested, it 
> seems that any device that performs any kind of *heating* instantly uses 
> many times more power than anything else. I emphasize: MANY TIMES more 
> power. Not 20% more, not 50% more, but nearer to 1000% more! Heck, even 
> the vacuum cleaner (surely a high power device) in fact uses a fraction 
> of the power that the toaster does!
> 
> Can anybody suggest why this might be? I mean, huge powerful electric 
> motors use a fair bit of power, but it's almost insignificant compared 
> to heating devices. Why does heating things require so much power?
> 
> Also, I notice that my PC uses about 10x as much power as my laptop. 
> There are two possible explanations for this:
> 
> 1. My PC is (or recently was) leading edge, whereas my laptop was pretty 
> much old hat even when it was purchased.
> 
> 2. It's a laptop. It's designed to use less power.
> 
> PS. We have *another* Intel Core 2 Duo laptop at work. And just like the 
> first one, it seems to be utterly impossible to make it heat up, no 
> matter how much number chrunching I throw at it. How do they manage that?
>

Post a reply to this message

Orchid XP v3 wrote:
> I haven't tested out the TV yet, but of all the stuff I have tested, it 
> seems that any device that performs any kind of *heating* instantly uses 
> many times more power than anything else.

It's amazing how much potential there is in even a small amount of heat, 
isn't it?

By the way, while heating so far beats all other estimates, IIRC cooling 
requires even *more* juice for the same amount of temperature change. 
Of course, I don't know if your air conditioner will suck in as much 
heat as your kettle puts out, but AC is probably the greatest drain on 
the power grid pretty much anywhere in the world.

> Also, I notice that my PC uses about 10x as much power as my laptop. 
> There are two possible explanations for this:
> 
> 1. My PC is (or recently was) leading edge, whereas my laptop was pretty 
> much old hat even when it was purchased.
> 
> 2. It's a laptop. It's designed to use less power.

Both.

> PS. We have *another* Intel Core 2 Duo laptop at work. And just like the 
> first one, it seems to be utterly impossible to make it heat up, no 
> matter how much number chrunching I throw at it. How do they manage that?

Several ways, one of which being that it slows itself down if it gets 
too hot :)

-- 
...Ben Chambers
www.pacificwebguy.com

Post a reply to this message

On Sat, 01 Sep 2007 19:11:57 +0100, Orchid XP v3 wrote:

> I haven't tested out the TV yet, but of all the stuff I have tested, it
> seems that any device that performs any kind of *heating* instantly uses
> many times more power than anything else. I emphasize: MANY TIMES more
> power. Not 20% more, not 50% more, but nearer to 1000% more! Heck, even
> the vacuum cleaner (surely a high power device) in fact uses a fraction
> of the power that the toaster does!
> 
> Can anybody suggest why this might be? I mean, huge powerful electric
> motors use a fair bit of power, but it's almost insignificant compared
> to heating devices. Why does heating things require so much power?

Heat is generated through increased electrical resistance; in order to 
heat a heating element up, you need to push more electricity through it.

http://en.wikipedia.org/wiki/Heating_element is a good starting point.

Jim

Post a reply to this message

I think they are starting to use microwaves in
indirect heating in some high end ovens.  The
microwaves heat some sort of target element,
then pump air thru it, the oven door can be
opened without fear of microwave leakage.
It reduces cooking time, but I bet it's better
in terms of power usage too.

Post a reply to this message

Tim Attwood wrote:
> I think they are starting to use microwaves in
> indirect heating in some high end ovens.  The
> microwaves heat some sort of target element,
> then pump air thru it, the oven door can be
> opened without fear of microwave leakage.
> It reduces cooking time, but I bet it's better
> in terms of power usage too. 

There are also induction cookers which are significantly more efficient 
than traditional conduction cooktops.

http://en.wikipedia.org/wiki/Induction_cooktop

Lance.

thezone - thezone.firewave.com.au

Post a reply to this message

Orchid XP v3 wrote:
> Can anybody suggest why this might be?

It's because heat represents a huge amount of energy.

For instance, the humble calorie, the amount of energy required to raise 
a single gram of water by one degree celsius, is the same amount of 
energy required to lift that same gram of water about 387 meters in 
Earth's gravity, or accelerate it from zero to 87 meters per second.

Regards,
John

Post a reply to this message

Orchid XP v3 wrote:
> PS. We have *another* Intel Core 2 Duo laptop at work. And just like the 
> first one, it seems to be utterly impossible to make it heat up, no 
> matter how much number chrunching I throw at it. How do they manage that?

I have a 2Gig Celeron laptop (from 2003) that gets very hot when it has 
to crunch, like during a POV-Ray render.

Regards,
John

Post a reply to this message

On Sat, 01 Sep 2007 18:19:25 -0700, Tim Attwood wrote:

> I think they are starting to use microwaves in indirect heating in some
> high end ovens.  The microwaves heat some sort of target element, then
> pump air thru it, the oven door can be opened without fear of microwave
> leakage. It reduces cooking time, but I bet it's better in terms of
> power usage too.

Probably, but I'm always reminded of the phrase "there ain't no such 
thing as a free lunch" - when it comes to generating heat, physics still 
applies.  Doesn't mean things can't be more efficient than they currently 
are, though.

Jim

Post a reply to this message

Thibaut Jonckheere wrote:

> No answer (sorry), but two questions :
> 
> - What device do you use to mesure power ? Is it expensive ?

I said it in my blog, and I'll say it again here:

http://www.maplin.co.uk/search.aspx?menuno=80119&MenuName=Power%20and%20Energy%20Monitors&FromMenu=y&worldid=-6&doy=28m8

Roughly £30.

> - Have you tried to mesure the power used by electronic devices (TV, 
> HiFi, etc.) when they are on standby ? I find it difficult to get a 
> estimation for this, and it seems to vary greatly even among similar 
> devices ?

Some devices actually use 0 W when off. (A few use 0 W even when on. For 
example, the clothes iron, once it's hot.) Most things seem to use less 
than 5 W while on standby.

And yes, the TV is one thing I still haven't got round to measuring!

-- 
http://blog.orphi.me.uk/

Post a reply to this message

>> Can anybody suggest why this might be?
> 
> It's because heat represents a huge amount of energy.
> 
> For instance, the humble calorie, the amount of energy required to raise 
> a single gram of water by one degree celsius, is the same amount of 
> energy required to lift that same gram of water about 387 meters in 
> Earth's gravity, or accelerate it from zero to 87 meters per second.

Damn... pitty we can't use heat to do *useful* stuff!

-- 
http://blog.orphi.me.uk/

Post a reply to this message

"Orchid XP v3" <voi### [at] devnull> a écrit dans le message de news: 
46daa206@news.povray.org...
>
> Damn... pitty we can't use heat to do *useful* stuff!
>
Watt?

Marc

Post a reply to this message

> Probably, but I'm always reminded of the phrase "there ain't no such
> thing as a free lunch" - when it comes to generating heat, physics still
> applies.  Doesn't mean things can't be more efficient than they currently
> are, though.

Problem with conventional cookers is they tend to heat up your kitchen 
too...

Post a reply to this message

> Damn... pitty we can't use heat to do *useful* stuff!

You mean like to boil water to turn a big turbine that generates enough 
electricity to run a city?

Post a reply to this message

> The most thirsty device I've found so far is... the kettle. It uses in 
> excess of 3,000 W for the entire duration that you try to boil water with 
> it.

That's about the most you will get out of a UK mains socket (230 V x 13 
amps), but you'll probably find your electric cooker uses more when you have 
everything switched on (it's usually wired directly into the distribution 
board, so probably can't test it with your gizmo).

Post a reply to this message

>> - What device do you use to mesure power ? Is it expensive ?
> 
> I said it in my blog, and I'll say it again here:

Believe it or not, but I started reading your blog a few days ago... But 
I haven't gone through all the archives.


> 
>
http://www.maplin.co.uk/search.aspx?menuno=80119&MenuName=Power%20and%20Energy%20Monitors&FromMenu=y&worldid=-6&doy=28m8

> 
> 
> Roughly £30.
>

Thanks

>> - Have you tried to mesure the power used by electronic devices (TV, 
>> HiFi, etc.) when they are on standby ? I find it difficult to get a 
>> estimation for this, and it seems to vary greatly even among similar 
>> devices ?
> 
> Some devices actually use 0 W when off. (A few use 0 W even when on. For 
> example, the clothes iron, once it's hot.) Most things seem to use less 
> than 5 W while on standby.
> I should mesure this at home, to know for which devices it is meaningful 
to put power off for energy savings (you know, global waarming etc.), 
and for which devices it is not worth the effort.

5W on standby is quite a lot already : for one year (non-stop), it makes 
roughly 44kWh, which is comparable to your kettle running at 3000W for 
~14h (and how many cups of tea :-P ?) !


Thibaut




> And yes, the TV is one thing I still haven't got round to measuring!
>

Post a reply to this message

Thibaut Jonckheere wrote:

> 5W on standby is quite a lot already : for one year (non-stop), it makes 
> roughly 44kWh, which is comparable to your kettle running at 3000W for 
> ~14h (and how many cups of tea :-P ?) !

Yeah, it is really.

I was quite surprised that my PC uses 4 W even when it's "turned off"...

(I'm not sure I *want* to know what my laser printer uses. That's 
permanently turned on too!)

-- 
http://blog.orphi.me.uk/

Post a reply to this message

scott wrote:
>> The most thirsty device I've found so far is... the kettle. It uses in 
>> excess of 3,000 W for the entire duration that you try to boil water 
>> with it.
> 
> That's about the most you will get out of a UK mains socket (230 V x 13 
> amps), but you'll probably find your electric cooker uses more when you 
> have everything switched on (it's usually wired directly into the 
> distribution board, so probably can't test it with your gizmo).

You're right: I can't. I have a gas cooker. ;-)

I just find it bizzare that this huge washing machine, spinning away to 
violently that it's deafening to stand near and you'd probably be 
injured if you touched it, uses about 5% of the power of a teeny little 
kettle. Far out!

I'm currently measuring the fridge. Surprisingly, it uses a whole 100 W 
when the compressor is running. (I was expecting lower.) OTOH, it 
doesn't run for long...

PS. 230 V? I thought it was 250 V...

-- 
http://blog.orphi.me.uk/

Post a reply to this message

"Orchid XP v3" <voi### [at] devnull> a écrit dans le message de news: 
46dac2d2$1@news.povray.org...
> I just find it bizzare that this huge washing machine, spinning away to 
> violently that it's deafening to stand near and you'd probably be injured 
> if you touched it, uses about 5% of the power of a teeny little kettle. 
> Far out!
Did you measure your washing machine while it is warming water?

Marc

Post a reply to this message

"Orchid XP v3" <voi### [at] devnull> wrote in message 
news:46dac2d2$1@news.povray.org...
> scott wrote:
>> That's about the most you will get out of a UK mains socket (230 V x 13 
>> amps), but you'll probably find your electric cooker uses more when you 
>> have everything switched on (it's usually wired directly into the 
>> distribution board, so probably can't test it with your gizmo).
>
> You're right: I can't. I have a gas cooker. ;-)

Heh, touché!  :-)

> I just find it bizzare that this huge washing machine, spinning away to 
> violently that it's deafening to stand near and you'd probably be injured 
> if you touched it, uses about 5% of the power of a teeny little kettle. 
> Far out!

A. Didn't you say it uses 600W at final spin speed?  That's 20% of 3000...

B. It only seems bizarre because you already had decided on the way things 
are before learning even the first fact about them (ie. do an experiment 
like this, or study electrical theory).  It's really cool to go "wow!" and 
be excited about new discoveries.  But you are kinda saying that things you 
haven't seen should behave exactly as your head imagined it, rather than 
work the way it always has done, only waiting for you to come along and 
discover it.  Actually, now I think of it, you do that rather too often, 
which is unfortunate because you limit yourself then...   :'-s

N'est-ce-pas?   ;-)

Post a reply to this message

On Sun, 02 Sep 2007 15:02:00 +0100, Orchid XP v3 wrote:

> I was quite surprised that my PC uses 4 W even when it's "turned off"...

Does it support Wake on LAN?  If so, then there's got to be some power 
consumed to keep it awake enough to recognise a signal coming in saying 
"wake up now".

Jim

Post a reply to this message

On Sun, 02 Sep 2007 14:27:08 +0200, scott wrote:

>> Probably, but I'm always reminded of the phrase "there ain't no such
>> thing as a free lunch" - when it comes to generating heat, physics
>> still applies.  Doesn't mean things can't be more efficient than they
>> currently are, though.
> 
> Problem with conventional cookers is they tend to heat up your kitchen
> too...

I'm with you on that....we've got an old Wedgewood stove (very nice 
stove) with dual ovens, but our evaporative cooler blows the burners, so 
we have to turn the cooler off while using the stove, or the flames dance 
everywhere.  That just makes it that much more difficult to cook in 100 
degree+ temps.

Jim

Post a reply to this message

>> I was quite surprised that my PC uses 4 W even when it's "turned off"...
> 
> Does it support Wake on LAN?  If so, then there's got to be some power 
> consumed to keep it awake enough to recognise a signal coming in saying 
> "wake up now".

Yes, but 4 W!!!!  4 mW should be enough.

Post a reply to this message

> I just find it bizzare that this huge washing machine, spinning away to 
> violently that it's deafening to stand near and you'd probably be injured 
> if you touched it, uses about 5% of the power of a teeny little kettle. 
> Far out!

And then you'd probably also be surprised how loud your speakers are when 
you feed just 5 W into them.

> I'm currently measuring the fridge. Surprisingly, it uses a whole 100 W 
> when the compressor is running. (I was expecting lower.) OTOH, it doesn't 
> run for long...

> PS. 230 V? I thought it was 250 V...

IIRC the spec was changed from 240 +/- 10% to 230 +15% -5% (or something 
equally stupid) to get us inline with Europe.  Doesn't your meter tell you 
the voltage too?

Post a reply to this message

On Sun, 02 Sep 2007 20:00:18 +0200, scott wrote:

>>> I was quite surprised that my PC uses 4 W even when it's "turned
>>> off"...
>> 
>> Does it support Wake on LAN?  If so, then there's got to be some power
>> consumed to keep it awake enough to recognise a signal coming in saying
>> "wake up now".
> 
> Yes, but 4 W!!!!  4 mW should be enough.

Perhaps, depends on what other features the kit has, though.

I know, for example, that the system I have here at my feet has an ATX 
board, which means the "power" switch is solid state rather than a 
physical switch.  That means the board is powered all the time (when the 
power supply switch is on at the back of the system).

Jim

Post a reply to this message

>> I was quite surprised that my PC uses 4 W even when it's "turned off"...
> 
> Does it support Wake on LAN?  If so, then there's got to be some power 
> consumed to keep it awake enough to recognise a signal coming in saying 
> "wake up now".

It probably does support Wake on LAN. I really, *really* hope I have 
that disabled though... (It's hard to tell!)

-- 
http://blog.orphi.me.uk/

Post a reply to this message

scott wrote:
>>> I was quite surprised that my PC uses 4 W even when it's "turned off"...
>>
>> Does it support Wake on LAN?  If so, then there's got to be some power 
>> consumed to keep it awake enough to recognise a signal coming in 
>> saying "wake up now".
> 
> Yes, but 4 W!!!!  4 mW should be enough.

I notice that, for example, the battery charger for my mouse continues 
to charge even while the PC is "off". Also, the LEDs on my MIDI 
interface still twinkle. And the USB light on my external audio card 
still lights up. All of these things go out when I unplug the PC from 
the mains. (Or just flip the switch on the PSU.)

Even so... that takes it up to, what, 19 mW? I don't know what the other 
3,981 W is for...

(That's actually slightly unfair. The meter is only accurate to the 
nearest 1 W, and I don't know what its rounding mode is...)

Convesly, the PC uses *less* power than I was expecting when turned on, 
so...

-- 
http://blog.orphi.me.uk/

Post a reply to this message

>> I just find it bizzare that this huge washing machine, spinning away 
>> to violently that it's deafening to stand near and you'd probably be 
>> injured if you touched it, uses about 5% of the power of a teeny 
>> little kettle. Far out!
> 
> And then you'd probably also be surprised how loud your speakers are 
> when you feed just 5 W into them.

Oh... no, not really. I mean, sound vibrations are really, *really* 
tiny. (Think about it; even when the sound is turned up painfully loud, 
the speaker cones move by such a tiny amount you can't even see them 
move at all!)

AFAIK, the reason we have 200 W amplifiers and speakers isn't so much 
because it takes that much electricity to move air around, but to reduce 
RF pickup in the speaker wire... (Or rather, to reduce the 
*signifigance* of such pickup.)

>> PS. 230 V? I thought it was 250 V...
> 
> IIRC the spec was changed from 240 +/- 10% to 230 +15% -5% (or something 
> equally stupid) to get us inline with Europe.  Doesn't your meter tell 
> you the voltage too?

The mater claims 249.98 V.

Also, 49.97 Hz. (So much for "they keep it to exactly 50 Hz to help all 
those clocks that use it". The frequency waivers all over the place!)

-- 
http://blog.orphi.me.uk/

Post a reply to this message

>> I just find it bizzare that this huge washing machine, spinning away to 
>> violently that it's deafening to stand near and you'd probably be injured 
>> if you touched it, uses about 5% of the power of a teeny little kettle. 
>> Far out!

> Did you measure your washing machine while it is warming water?

Yes. Then it goes up to about 25% of what the kettle uses. (Mind you, 
the kettle *boils* the water, the washing machine merely makes it 
slightly warm, and takes several minutes to do even that...)

-- 
http://blog.orphi.me.uk/

Post a reply to this message

>> I just find it bizzare that this huge washing machine, spinning away 
>> to violently that it's deafening to stand near and you'd probably be 
>> injured if you touched it, uses about 5% of the power of a teeny 
>> little kettle. Far out!
> 
> A. Didn't you say it uses 600W at final spin speed?  That's 20% of 3000...

Your powers of mental arithmetic greatly exceed mine.

> B. It only seems bizarre because you already had decided on the way 
> things are before learning even the first fact about them (ie. do an 
> experiment like this, or study electrical theory).  It's really cool to 
> go "wow!" and be excited about new discoveries.  But you are kinda 
> saying that things you haven't seen should behave exactly as your head 
> imagined it, rather than work the way it always has done, only waiting 
> for you to come along and discover it.  Actually, now I think of it, you 
> do that rather too often, which is unfortunate because you limit 
> yourself then...   :'-s

I didn't say I don't believe it. I just said it seems really bizzare and 
puzzling, that's all.

Gee, I wonder what our lawn mower uses...

-- 
http://blog.orphi.me.uk/

Post a reply to this message

On Sun, 02 Sep 2007 22:05:17 +0200, Orchid XP v3 <voi### [at] devnull> wrote:
>>> PS. 230 V? I thought it was 250 V...
>>  IIRC the spec was changed from 240 +/- 10% to 230 +15% -5% (or  
>> something equally stupid) to get us inline with Europe.  Doesn't your  
>> meter tell you the voltage too?
>
> The mater claims 249.98 V.

Still within tolerance.

http://en.wikipedia.org/wiki/Mains_electricity#Voltage_levels


> Also, 49.97 Hz. (So much for "they keep it to exactly 50 Hz to help all  
> those clocks that use it". The frequency waivers all over the place!)

http://en.wikipedia.org/wiki/Mains_electricity#Frequency_stability
http://www.dynamicdemand.co.uk/grid.htm



-- 
FE

Post a reply to this message

Orchid XP v3 wrote:
>>> Can anybody suggest why this might be?
>>
>>
>> It's because heat represents a huge amount of energy.
>>
>> For instance, the humble calorie, the amount of energy required to 
>> raise a single gram of water by one degree celsius, is the same amount 
>> of energy required to lift that same gram of water about 387 meters in 
>> Earth's gravity, or accelerate it from zero to 87 meters per second.
> 
> Damn... pitty we can't use heat to do *useful* stuff!

Heat already does useful things.  For instance, it causes cute girls to 
wear skimpy clothing.

Regards,
John

Post a reply to this message

On Sun, 02 Sep 2007 20:58:04 +0100, Orchid XP v3 wrote:

>  I really, *really* hope I have that
> disabled though... (It's hard to tell!)

BIOS settings.  But it's not exactly easy to learn the wake-up code from 
outside a NATted connection.  You've got to know the MAC address of the 
system, IIRC.

Yep, according to http://en.wikipedia.org/wiki/Wake-on-LAN the magic 
packet is set over a connectionless protocol (UDP, IPX) with "FF FF FF FF 
FF FF FF" (in hex, hopefully obviously) plus 16 repetitions of the target 
machine's MAC address, plus a 4-6 byte password.

So I don't think you have to worry about me turning your machine on from 
half a world away.

Jim

Post a reply to this message

Orchid XP v3 wrote:
> Can anybody suggest why this might be? I mean, huge powerful electric 

	They just are.

	I find it interesting that you're focusing on power rather than energy. 
How long do you spend boiling water vs how long is the washer running?


-- 
Atheism is a non-prophet organization.


                     /\  /\               /\  /
                    /  \/  \ u e e n     /  \/  a w a z
                        >>>>>>mue### [at] nawazorg<<<<<<
                                    anl

Post a reply to this message

>> Yes, but 4 W!!!!  4 mW should be enough.
>
> Perhaps, depends on what other features the kit has, though.

How about running an LCD panel, transmitting and receiving data from a 
base-station 10s of miles away, interpreting incoming data packets, waiting 
for key presses?  All for 10 mW.

> I know, for example, that the system I have here at my feet has an ATX
> board, which means the "power" switch is solid state rather than a
> physical switch.  That means the board is powered all the time (when the
> power supply switch is on at the back of the system).

The main point is that mainboard and PSU makers have no incentive to make a 
low power and efficient "off" state.  Really, such a small fraction of 
people/companies will make a decision based on the efficiency of the off 
state it is not worth it at all.

Post a reply to this message

> Even so... that takes it up to, what, 19 mW? I don't know what the other 
> 3,981 W is for...

Heat.

> Convesly, the PC uses *less* power than I was expecting when turned on, 
> so...

Is that with or without POV rendering? ;-)  Go on then, tell us how much it 
would cost to do a 9 month render...

Post a reply to this message

> Oh... no, not really. I mean, sound vibrations are really, *really* tiny. 
> (Think about it; even when the sound is turned up painfully loud, the 
> speaker cones move by such a tiny amount you can't even see them move at 
> all!)

Huh?  Even at normal listening volumes I can see the bass cones move on 
mine...  Try feeding a 20 Hz sine wave in and watch the cone...  These are 
only perhaps 6" drivers, nothing spectacular.  Mind you, I have never 
noticed the tiny 2" cones move on my PC speakers.

> AFAIK, the reason we have 200 W amplifiers and speakers isn't so much 
> because it takes that much electricity to move air around, but to reduce 
> RF pickup in the speaker wire... (Or rather, to reduce the *signifigance* 
> of such pickup.)

Huh?  You are saying that they deliberately make speakers less efficient so 
that a higher voltage can be used to drive them?  I've never heard that 
before.  Also I have never seen much "serious" hi-fi rated at anything like 
200 W for home use.  IME 15 W per channel is plenty to fill a medium sized 
room very loudly, perhaps if you live in a very large house and like 
listening to music very loud you'd want 200 W.

> The mater claims 249.98 V.

Sounds ok to me, the voltage will fluctuate a lot depending on lots of 
factors, like how much power people are using around you etc.  Try measuring 
the voltage at different times of the day...

> Also, 49.97 Hz. (So much for "they keep it to exactly 50 Hz to help all 
> those clocks that use it". The frequency waivers all over the place!)

And you think your meter is accurate to +/- 0.03 Hz?  It's worth noting that 
the national grid in the UK keeps all power stations interconnected so all 
generators *must* make power at the same frequency.  If everyone in the 
country turned on their kettles then the frequency and voltage would 
probably drop significantly...

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On Mon, 03 Sep 2007 08:45:39 +0200, scott wrote:

>>> Yes, but 4 W!!!!  4 mW should be enough.
>>
>> Perhaps, depends on what other features the kit has, though.
> 
> How about running an LCD panel, transmitting and receiving data from a
> base-station 10s of miles away, interpreting incoming data packets,
> waiting for key presses?  All for 10 mW.

Well, the distance to the base station doesn't matter unless it's 
wireless, then it's just the transmitter power.

>> I know, for example, that the system I have here at my feet has an ATX
>> board, which means the "power" switch is solid state rather than a
>> physical switch.  That means the board is powered all the time (when
>> the power supply switch is on at the back of the system).
> 
> The main point is that mainboard and PSU makers have no incentive to
> make a low power and efficient "off" state.  Really, such a small
> fraction of people/companies will make a decision based on the
> efficiency of the off state it is not worth it at all.

Very true.

Jim

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>> How about running an LCD panel, transmitting and receiving data from a
>> base-station 10s of miles away, interpreting incoming data packets,
>> waiting for key presses?  All for 10 mW.
>
> Well, the distance to the base station doesn't matter unless it's
> wireless, then it's just the transmitter power.

I was just illustrating that a normal mobile phone can do all that stuff 
(both transmitting and receiving to the base station) for around 10 mW.

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scott wrote:
>> Even so... that takes it up to, what, 19 mW? I don't know what the 
>> other 3,981 W is for...
> 
> Heat.
> 
>> Convesly, the PC uses *less* power than I was expecting when turned 
>> on, so...
> 
> Is that with or without POV rendering? ;-)

Without *anything* happening, it uses 110 W.

With my stonking-great video card with a fan the size of a plannet, it 
uses 190 W. (Roughly. It waivers a lot.) During the boot sequence it 
tops 280 W. (Presumably when all those electric motors all start up at 
once...)

Actually, what the heck...

http://blog.orphi.me.uk/about/power

(Table of my work so far.)

-- 
http://blog.orphi.me.uk/

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John VanSickle wrote:

>> Damn... pitty we can't use heat to do *useful* stuff!
> 
> Heat already does useful things.  For instance, it causes cute girls to 
> wear skimpy clothing.

Hey, neat!

(Pitty it's too damn hot to do anything about it...)

-- 
http://blog.orphi.me.uk/

Post a reply to this message

>> Oh... no, not really. I mean, sound vibrations are really, *really* 
>> tiny. (Think about it; even when the sound is turned up painfully 
>> loud, the speaker cones move by such a tiny amount you can't even see 
>> them move at all!)
> 
> Huh?  Even at normal listening volumes I can see the bass cones move on 
> mine...  Try feeding a 20 Hz sine wave in and watch the cone...  These 
> are only perhaps 6" drivers, nothing spectacular.  Mind you, I have 
> never noticed the tiny 2" cones move on my PC speakers.

I have never seen any cone on any speaker move visibly - no matter how 
much physical pain my ears were in. See, human ears are, like, *really* 
sensitive...

> Huh?  You are saying that they deliberately make speakers less efficient 
> so that a higher voltage can be used to drive them?  I've never heard 
> that before.

Yes.

> Also I have never seen much "serious" hi-fi rated at 
> anything like 200 W for home use.  IME 15 W per channel is plenty to 
> fill a medium sized room very loudly, perhaps if you live in a very 
> large house and like listening to music very loud you'd want 200 W.

Hmm, I think my amplifier (nothing special) is rated at 60 W per 
channel. (IIRC, into 8 ohms at 1 kHz.)

That's 60 W RMS by the way. Not like the "100 W" portable thing I once 
owned that was actually 0.5 W RMS. ;-)

>> The mater claims 249.98 V.
> 
> Sounds ok to me, the voltage will fluctuate a lot depending on lots of 
> factors, like how much power people are using around you etc.  Try 
> measuring the voltage at different times of the day...

Wait... the *voltage* changes depending on how much you use it? That's 
odd. I thought that potential difference was always constant, and it's 
only *current* that changes...

>> Also, 49.97 Hz. (So much for "they keep it to exactly 50 Hz to help 
>> all those clocks that use it". The frequency waivers all over the place!)
> 
> And you think your meter is accurate to +/- 0.03 Hz?

Actually, the instruction book (which is oddly large for such a simple 
device) states the accuracy for all readings. I forget what it says for 
the frequency...

-- 
http://blog.orphi.me.uk/

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Mueen Nawaz wrote:

>     I find it interesting that you're focusing on power rather than 
> energy. How long do you spend boiling water vs how long is the washer 
> running?

Well, that's the other part. The fridge doesn't use much power, but it's 
permanently switched on. (Altough obviously it only draws any current 
now and then.) So far it's clocked up a fair number of kWh...

-- 
http://blog.orphi.me.uk/

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Orchid XP v3 wrote:
>>> I just find it bizzare that this huge washing machine, spinning away 
>>> to violently that it's deafening to stand near and you'd probably be 
>>> injured if you touched it, uses about 5% of the power of a teeny 
>>> little kettle. Far out!
>>
>> And then you'd probably also be surprised how loud your speakers are 
>> when you feed just 5 W into them.
> 
> Oh... no, not really. I mean, sound vibrations are really, *really* 
> tiny. (Think about it; even when the sound is turned up painfully loud, 
> the speaker cones move by such a tiny amount you can't even see them 
> move at all!)
> 
have you taken into account that the overlap in frequency resolution of 
your ears and eyes is very small? You can not hear anything below 20 Hz
or see anything above 50 Hz.
> AFAIK, the reason we have 200 W amplifiers and speakers isn't so much 
> because it takes that much electricity to move air around, but to reduce 
> RF pickup in the speaker wire... (Or rather, to reduce the 
> *signifigance* of such pickup.)
> 
>>> PS. 230 V? I thought it was 250 V...
>>
>> IIRC the spec was changed from 240 +/- 10% to 230 +15% -5% (or 
>> something equally stupid) to get us inline with Europe. 
At the same time the *rest* of Europe changed from 220 to exactly the 
same specification. FYI the UK is *within* Europe.

>> Doesn't your meter tell you the voltage too?
> 
> The mater claims 249.98 V.
> 
> Also, 49.97 Hz. (So much for "they keep it to exactly 50 Hz to help all 
> those clocks that use it". The frequency waivers all over the place!)
> 
RTFM The instantaneous frequency (how is that for an oxymoron) may vary, 
but there will be exactly 432000 cycles in a day.

Post a reply to this message

andrel wrote:

>> Oh... no, not really. I mean, sound vibrations are really, *really* 
>> tiny. (Think about it; even when the sound is turned up painfully 
>> loud, the speaker cones move by such a tiny amount you can't even see 
>> them move at all!)
>>
> have you taken into account that the overlap in frequency resolution of 
> your ears and eyes is very small? You can not hear anything below 20 Hz
> or see anything above 50 Hz.

And when I start up the engine of my car, the various parts move far too 
fast for the eye to follow. But you *can* see the blur of moving 
objects, and there is little doubt that they're moving. ;-)

>> Also, 49.97 Hz. (So much for "they keep it to exactly 50 Hz to help 
>> all those clocks that use it". The frequency waivers all over the place!)
>>
> RTFM The instantaneous frequency (how is that for an oxymoron) may vary, 
> but there will be exactly 432000 cycles in a day.

Behold: Differential calculus. ;-)

-- 
http://blog.orphi.me.uk/

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Orchid XP v3 wrote:
> Gee, I wonder what our lawn mower uses...

Mine has a nifty engine that breaks down all sorts of bio matter into 
simple carbohydrates and then burns them.  It's flexible enough to work 
on matter as diverse as fruits, grains, and meats, although certain 
spices have been known to give it trouble.  Also, you need a fair amount 
of fiber mixed in, otherwise the whole thing can get clogged.

-- 
...Ben Chambers
www.pacificwebguy.com

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Orchid XP v3 wrote:
> andrel wrote:
> 
>>> Oh... no, not really. I mean, sound vibrations are really, *really* 
>>> tiny. (Think about it; even when the sound is turned up painfully 
>>> loud, the speaker cones move by such a tiny amount you can't even see 
>>> them move at all!)
>>>
>> have you taken into account that the overlap in frequency resolution 
>> of your ears and eyes is very small? You can not hear anything below 
>> 20 Hz
>> or see anything above 50 Hz.
> 
> And when I start up the engine of my car, the various parts move far too 
> fast for the eye to follow. But you *can* see the blur of moving 
> objects, and there is little doubt that they're moving. ;-)
Why do you think that those frequencies are far above 50 Hz?
What sound does your motor make? Can you find the base frequency on your 
keyboard?

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"Orchid XP v3" <voi### [at] devnull> wrote in message
news:46dc4c7a$1@news.povray.org...
> John VanSickle wrote:
>
> >> Damn... pitty we can't use heat to do *useful* stuff!
> >
> > Heat already does useful things.  For instance, it causes cute girls to
> > wear skimpy clothing.
>
> Hey, neat!
>
> (Pitty it's too damn hot to do anything about it...)
>

Two words...

Swimming pool

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On Mon, 03 Sep 2007 10:31:33 +0200, scott wrote:

>>> How about running an LCD panel, transmitting and receiving data from a
>>> base-station 10s of miles away, interpreting incoming data packets,
>>> waiting for key presses?  All for 10 mW.
>>
>> Well, the distance to the base station doesn't matter unless it's
>> wireless, then it's just the transmitter power.
> 
> I was just illustrating that a normal mobile phone can do all that stuff
> (both transmitting and receiving to the base station) for around 10 mW.

I *think* the xmit power of a cell phone is a bit more than that...But 
I'd have to check.

Jim

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Jim Henderson wrote:
> I *think* the xmit power of a cell phone is a bit more than that...But 
> I'd have to check.

Depends on the phone system. CDMA was originally designed to be an 
undetectable transmitter for military use. IIRC, its power ranges 
between 2.5mW and 5mw.

-- 
   Darren New / San Diego, CA, USA (PST)
     Remember the good old days, when we
     used to complain about cryptography
     being export-restricted?

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