joules, watts and volts question

aUt0eXebat

Banned
Oct 9, 2000
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1) How many watts a volt
2) How many joules in a watt or volt.... or what are they??

And I got a 1024 Joule surge protector, is that pretty good?
 

sohcrates

Diamond Member
Sep 19, 2000
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amps are a measure of current through a wire, volts are a measure of the difference in potential between two points, watts are a measure of power, and joules are a foreign measure of power...so joules and watts are kinda like meters and feet.

the converstion between the two eludes me at the moment...it's a simple one though, and you'd be able to tell if your UPS is suited for the job pretty easily once you do the easy math. if you get desperate, pm me saturday when i'm back at school and i'll pull out the 'ole conversion table.
 

brewerbob

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Dec 31, 2000
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There are no watts in a volt and vise versa. A watt is the unit of measure for power. P=I*E that is current times voltage. Actually power is the rate of doing work or converting from one form to another.

1 volt = 1 joule/coulomb

A coulomb is equal to 6. something times 10 to the 23rd power of electrons past a given point in on second.

A wall socket has 110v and 15 amps so will produce about 1650 watts (if your breaker doesn't trip too soon)

A joule is the unit of work (power) and energy in the MKS system.

Bet that doesn't help much huh?

Anyway, the joules thing is a bit fuzzy. I had to look it up in an electronics book and it didn't mention anything else about it.

Wait... here we go. W=Vlt (this and old book E=V) voltage x current x time

120v x 3amp x 12 s = 4230 joules.

So it seems that the joule rating you have is a function of three variables. A short bi spike it will block, a small long spike it will block but stay away from the big long spikes!!

 

Soccerman

Elite Member
Oct 9, 1999
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here's how I understand it:

the units that Watts represent, is Work/second. (work is the force exerted over a distance, which is Joules).

that means that in theory if you had an electric car, and accelerated fast enough to hit 60mph in 5 seconds, the amount of electricity used would be equal to if you hit 60 mph after 10 seconds. however the watts would be considerably higher.

I think of voltage as the energy within the electric flow (though that is somewhat misleading I think). the unit for Voltage is J/C or Joules/Coulomb. a Coulomb is a certain amount of electrons. 1 electron is (I think) 1.6X10^-19 Coulombs.

in order to convert from Volts to watts, you need at least one other number. the main equation for this is Watts=Amps*Volts.

Amps is basically the amount of coulombs passing a given point in a second.

so you end up with Coulombs/second * Joules/Coulomb= Joules/second.

the hardest part for me to understand is the Voltage one.. it's kind of a weird idea. it's the amount of work you can do with a charge that is in an electric field (I think).

you think that's hard? try understanding magnetism. it's SOMEWHAT like electric fields, but different. I don't like the explanation of what it is in todays science.. it doesn't make sense to me.
 

brewerbob

Senior member
Dec 31, 2000
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Voltage is merely a difference in potential, doesn't have anything to do with time. A coulomb is equal to 6.24 x10^18 electrons (simply a number of electrons). One ampere is the flow of one coulomb of electrons in a second.

I'm not real sure who does the counting to make sure an extra one doesn't sneak by :D