Why to us houses of 220 volts?
the Strange question - you will tell. How without electricity? At such number of electric devices and electronics. And I also do not speak about electricity in general. It is about alternating current of 220 volts and with a frequency of 50 hertz in sockets at our place. For example, the modern car not less apartment is stuffed with electronics and electrical equipment. But all at it, even the vacuum cleaner, the coffee maker, the refrigerator are powered a direct current with tension of 12 volts. And anything!
And houses we are forced to transform with big losses current from the electric socket to a low-voltage direct current, necessary for power supply of home electronics. Touch the charger of the mobile phone in operating time. It is warm. Means, much more energy is lost, than goes directly for battery charging of phone. What would you tell if the exchange office of currency took a half of the exchanged sum as the commission? And power supply units of TVs, computers, radio receivers and the other equipment also do it!
It would be much more favorable if houses in sockets at once as in cars, there was a direct current of 12 volts. More safely. And the stove and equipment, you ask, and lighting lamps? Or washing machine? But automobile experience shows that they can be designed and on food from 12 V. I it will not affect their performance data in any way. On the contrary, they will become safer. Just now they are calculated on what at us is at home. And all electronic equipment just without power supply units will become cheaper - they not only consume the additional electric power, but also make part of the price.
So from where in our sockets the high voltage and alternating current undertook? Especially as the first source - volts the column - gave a direct current. The matter is that it is more favorable to transfer alternating current of a high voltage to long distances on power lines. The bigger current goes on a wire, the it is more than loss from - for its heatings. From school the formula is known to all that electric power is equal to work of size of current at tension size. Follows from it that the tension is higher, the smaller current is required for transfer of the same power. Tension of the high voltage line reaches hundreds of thousands of volts. And for increase of tension, and then the return decrease the transformers demanding alternating current are used.
And why a final voltage of 220 V or 110 in some countries? It goes down to these sizes on regional substations and then is distributed on houses. 50 years ago lamp radio receiver and the TV were the only electronics in our houses. For their food such tension was required just approximately. Now the number of the last applied radio tubes - electronic tubes of TVs and monitors of computers is promptly reduced. It is a high time to think of transfer of power supply networks to a direct current of a low voltage. Yes, thickness of electricity cables should be increased, but it will repeatedly pay off reduction of losses on transformation of the electric power and electrical safety increase.
For a start it is possible to have one low-voltage converter on the apartment with distributing on rooms parallel to an old electrical wiring. At cost it will not exceed the devices of protective shutdown which are available now. And the last will not be necessary at a safe tension any more. Then it is possible to reach also replacement of the available transformer substations. Than the converter - that it more economic is larger. Business it not simple for many reasons. But to think of it it is necessary to begin already now!]