Basics of electrical power
Electric power is the product of two quantities: current and voltage. These two quantities can vary with respect to time (AC power) or can be kept at constant levels (DC power).
Most refrigerators, air conditioners, pumps and industrial machinery use AC power whereas most computers and digital equipment use DC power (the digital devices you plug into the mains typically have an internal or external power adapter to convert from AC to DC power). AC power has the advantage of being easy to transform between voltages and is able to be generated and utilised by brushless machinery. DC power remains the only practical choice in digital systems and can be more economical to transmit over long distances at very high voltages (see HVDC).1415
The ability to easily transform the voltage of AC power is important for two reasons: Firstly, power can be transmitted over long distances with less loss at higher voltages. So in power systems where generation is distant from the load, it is desirable to step-up (increase) the voltage of power at the generation point and then step-down (decrease) the voltage near the load. Secondly, it is often more economical to install turbines that produce higher voltages than would be used by most appliances, so the ability to easily transform voltages means this mismatch between voltages can be easily managed.14
Solid state devices, which are products of the semiconductor revolution, make it possible to transform DC power to different voltages, build brushless DC machines and convert between AC and DC power. Nevertheless devices utilising solid state technology are often more expensive than their traditional counterparts, so AC power remains in widespread use.
How alone lay the electrical system?
Although many people isolated attempts to control the domestic installations, usually professional help is highly desirable especially in more complex cases. As far as changing a light bulb or perform other similar tasks require more visits electrician so much already in the case of laying wires or installation of distribution are more complicated. Isolated executed electrical installations can make later, at the stage of operational problems arise, for example, through the inclusion of too many devices to the power supply circuit may occur. So let's take care of it, to the more complex work carried out specialist, because working with electricity can be dangerous for inexperienced employee.
The knowledge needed for laying electrical installations
Laying the electrical system not only at home, but each object is not the simplest of tasks. First of all, you must have the appropriate skills in the field of electrical engineering. You must also have knowledge typically technical, that is how laid the cables, where assembled the so-called cans, and how spread out the electrical system, if we consider the whole house. Specific challenges are posed by various types of sockets and switches located in such areas, like the kitchen or bathroom. That is where there is the greatest danger, and to correctly assemble the installation you have to have not only knowledge but also experience.