Berkeley CSUA MOTD:Entry 33766
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2018/08/16 [General] UID:1000 Activity:popular
 8/16

 2004/9/26-27 [Science/Electric] UID:33766 Activity:high ```9/26 I was kinda of curious how much the little light on my power strip costs me each month. Does anyone know how I can figure it out? I assume it would depend on how many watts per second it uses, how can I find out such a thing? \_ Uhm, like less than a quarter a year. If you are that concerned you can ask a bum for some change... \_ That said, I read somewhere that the cumulative energy usage of appliances on standby, plus all the "little lights" in an average household is pretty high over any given year. Any facts about this? -John \_ http://www.engadget.com/entry/2486151161648138 \_ Measure the current and voltage. \_ For real-life power consumption measurement, I found the kill-a-watt incredibly useful: http://www.p3international.com/products/special/P4400/P4400-CE.html \_ Something like this: www.cyberguys.com/templates/searchdetail.asp?T1=112+0240 \- it would be interesting to learn: opening the fridge for 10 seconds = how much time for the "little light". \_ Related question, a watt is on Amp at 1 volt for what, one minute? \_ a watt is a joule per second, and an amp is a coulomb per second. a watt is also a volt times an amp. you could think of it as a volt times a coulomb per second, which makes sense, since voltage times charge has units of energy, so it's still energy per time. http://physics.nist.gov/cuu/Units/units.html \_ obGoogle: http://www.google.com/search?q=amp+joule+watt+second \_ A watt is one amp at one volt. A joule is one amp at one volt for one second. \_ So a kilowatt-hour is exactly 3.6 MJ then.. interesting. They should have just used MJs for reporting your monthly power usage. Less need for decimal pointage, and it's not a stupid unit. \_ KW is not a stupid unit. KWH is not a great scientific unit, but it makes a lot of sense in relation to electrical appliances and the like. c.f. "How much power does it take to run this light bulb for 1000 hours? 60KWH." \_ Another related question, I just read that AC-DC adapters are constantly sucking power regaurdless ow wether they are on or not. True? \_ Since they are warm even when the appliance is not in use, the answer should be "yes". There is some new design that is supposedly much more efficient but I haven't heard about it for years. \_ Watt is joule per second.```
2018/08/16 [General] UID:1000 Activity:popular
 8/16

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