Why United States uses 110 Volts where all other europian countries use 120  volts?
111272
this is because of they way americans obtain their electricity 110 volts is the kind of electricity which is produced by atomic nuclear energy the others use wather sun power and wind.
9252
There used to be "B" batteries in antique portable radios.  I believe that they were 45 Volts DC and were used to power vacuum tubes.  They are no longer needed for radios that plug into 110 Volt AC because a transformer can be used to obtain any needed voltage.  Radios that use chips need far less voltage than a B battery.  Incidentally it was called a battery because the casing contained multiple cells connected in series to boost the voltage, just as a cannon battery needs more than one cannon.  But see the source.
636324
I believe that 220V current has less line transmission loss over long distances.
729269
You will need a plug adapter and a power converter otherwise you will damage you power pack and laptop.\n\nOr the easier option is to buy a new power pack in Australia or buy one that works in Australia before you go (the compatible ones are cheaper than originals).\n\nNot only are the plugs different, but the main's current is also different.\n\nIn the US, the current running in the mains is approx 100-127v/60hz.\nIn Australia, the current running in the mains is approx 220-240v/50hz.\n\nPlease see here: http://en.wikipedia.org/wiki/Image:Map_of_the_world_coloured_by_voltage_and_frequency.png\nhttp://en.wikipedia.org/wiki/Domestic_AC_power_plugs_and_sockets
504290
The RMS (root-mean-square) value of AC voltage is NOT dependant on the frequency.  For a sine wave, it is .707 (half the square root of 2) multiplied by the peak voltage.\n\n120 and 240 volt circuits common in the US are derived from the center-tapped transformer, the center called the neutral.  This gives you 120V between each phase and neutral, and 240V between the phases.  An analogy that might make more sense is with batteries.  You can put two 9V batteries in series to get 18V, but you still have 9V across each battery.\n\nI think what you want to know from your question, is why do we have both 120V and 240V.  You can argue 120V is safer than 240V, but it is more historical that 110-120V is used in the US (many other countries, but not all, use 220-240V).  The reason for having 240V for some equipment is with a higher voltage it will draw less current, so smaller wires can be used.  Similar to power transmission using high voltages.\n\nThe safety ground, the 3rd round pin on a normal plug, is connected to the neutral at the electrical service.  The neutral is grounded (to the earth), and so is the safety ground, but that connection to the earth has nothing to do with its purpose.  This safety ground connects metal parts of equipment to the neutral, so if a fault in the equipment causes voltage on those metal parts, it will trip the circuit breaker rather than give you a shock (if you were touching it WHEN the fault occurred, you could get a shock before the circuit breaker tripped).  Another thing about the safety ground, it never carries current under normal conditions, and for that to be true it can only be connected to the neutral at the service.  NEVER connect a safety ground to a neutral at another point.\n\nAlso, never take the cover off your circuit breaker or fuse panel if you don't know what you are doing.  Suggesting someone take off the cover and poke around with a fluke is a bad idea.
152701
It goes from the substation to people's homes because of the difference in "electrical potential" which is measured in volts.  In the U.S., this difference is about 110 volts (relative to the earth or "ground").  Think of a ball rolling down a hill.  It goes from high potential (the top of the hill) to low potential (the bottom of the hill).\n\nAs to what direction it goes, it doesn't realy matter in one sense.  Electricity running through a light bulb will light it up regardless of the direction that the electrons are going.  So the power stations actually use alternating currents.  This means the levels of voltage go from high to very low (negative) several times per second (in fact it changes 60 times per second in the U.S., hence it's called 60 hertz).  So for a while the electrons flow one way, and then they flow the other.
128458
1.00 USD United States Dollars = 1.64038 DEM\nGermany Deutsche Marks (obsolete)\n\n1.00 USD United States Dollars = 7.84828 SEK\nSweden Kronor\n\nHowever,  On January 1, 1999, eleven of the countries in the European Economic and Monetary Union (EMU) decided to give up their own currencies and adopt the Euro (EUR) currency: Austria, Belgium, Finland, France, Germany, Ireland, Italy, Luxembourg, the Netherlands, Portugal, and Spain. Greece followed suit on January 1, 2001. The Vatican City also participated in the changeover. This changeover is now complete.\n\nEuro bank notes and coins began circulating in the above countries on January 1, 2002. At that time, all transactions in those countries were valued in Euro, and the "old" notes and coins of these countries were gradually withdrawn from circulation. The precise dates that each "old" currency ceased being legal tender are noted in the table below...\n\n1.00 USD United States Dollars =  0.838647 EUR\nEuro
293302
They developed appliances with different needs.\nBut they should standardize.  Tell me, which country do you tell to change their ENTIRE power grid structure?
704111
If by continent you mean continental Europe, then the voltages are compatible (240v in the UK and 220v in Europe)\n\nAll you need in this case is an adaptor plug as the plug shapes are different.
1082346
The "60 each" part of your question says you don't understand the most basic aspects of electricity.  Voltage is a measurement between two points.  Think of a 12V car battery.  It is 12 volts between the 2 terminals of the battery.  Another analogy:  two things that are 3 feet apart are 3 feet apart, not 1.5 feet each.\n\nDoubling 120 is 240, not 220, but I 220 is a commonly used number, like 110 for 120, but the standard voltages are 120 and 240.\n\nI think the point about doubling when you lose a neutral is talking about what is called a multiwire circuit.  The service into your house is the same, and some appliances like your dryer, have the same thing.  For a single phase case, a multiwire circuit has 2 phase (or hot) conductors and a neutral, with 120 volts between each phase and the neutral and 240 volts between the two phases.  This is created by a secondary winding on the utility transformer that is 240V, with a tap in the center which is grounded.  The tap is half way so it is 120V to each hot conductor.  If the neutral connection is lost, you still have 240V between the hot conductors, and all the 120V things in your house will be put in series.  For example, a couple light fixtures on 2 separate circuit breakers might be on the two opposite phases.  When the neutral is lost to the utility, there is still a connection of the neutral's of the lights, so you'll have the two lights in series and connected to 240V.  Each light will not have 240V though.  If the load on each phase were the same, removing the neutral will still leave 120V on each side.  That isn't likely, so one phase will get more than 120V (and generally cause damage) and the other phase will be less than 120V, and they will add to 240V.  It would be impossible for it to be so unbalanced that one phase would be 240V and the other would be 0.
853086
There are many countries in South America, some of them using the 120V 60Hz and some using the 220V 50Hz, most countries use the first but as you go further south the 220 is predominant..☺
1028004
Window units run off of 110 voltage x 2 = 220 voltage. Central air runs off 220 voltage. Central air circulates much better than window units. I'd opt for central air.
135636
because we are generatiing power in 11 kv.  then, we can easily transform this 11kv to 22kv,33kv,66kv,110kv or 132 kv. the reason for this easier transformation is, number of tunrs in secondary can be easily adjusted. for example if we need to transform 11kv to 66 kv, we need 6 times more number of turns in secondary. but if you want to transfer 11 kv to 44 kv,you need 4.4 times more turs in secondary. this 4.4 turns is not possible.that is why these types of voltage is using for electricity transmission
1040867
Using 3 phase current, it is possible to get 3 times the energy down the same wire - so it is much more efficient.  Each phase is 120 degrees out from the others, so the signal looks kind of like braided hair, when one phase is at the peak, the other two are crossing at 70%, one going up the other going down.  Once we get the energy to where we want to use it, then we can tap off the different phases for single phase use. \n\nI forget about the delta and wye stuff, it's been a while. \n\nCheers!
1007376
The voltage of 3 phase is the phase to phase voltage.  If you have a wye connection, the phase to neutral voltage is the phase to phase voltage divided by the square root of 3.  For 220 V would have phase to neutral of 127V.  You said earth.  There is no relationship to the earth unless you connect part of the transformer to earth.  If the secondary has a neutral which is connected to earth, then it would be 127V.
313707
Assuming you are using US household electricity (120VAC)\nP=V^2/R   R=V^2/P = (120)^2/1875= 7.68 ohms which is really small.
509058
No way.  And the evidence is easy to find, too.  Plug in a power converter and run something off it for a while, then put your hand on the converter -- it's hot, right?\n\nThat heat is *wasted energy* -- converting electricity from one voltage to another requires work to be done, and that work generates heat, which is the indication of the inherent inefficiences of the process.  If you then reconvert the electricity to 120V, you will experience a second inefficiency, evidenced as more heat lost.