In IEC connector or cable with a base (usually plastic) and a plug to connect to the socket (plug), if we put these two things we would get the named SCHUKO is the overall connector. The schuko not determine the type of connector. It would be determined by the specification of the International Electrotechnical Commision (IEC). We leave a small sample of Schukos internationally.

We can define the paper formats according to their measures and these are defined in ISO standard 216 one, which in turn includes the standard DIN 476. This applies in most of the world. I there are plenty of measures for the role, but the most used are the Serie A and to a lesser extent Serie B.

In Serie A, the most widely used format is the A4 (210x297mm) or also called "sheet" used in most printers and fotocopiadoras.

Series B is defined for intermediate sizes Series A. For example, the B4 is the intermediate size between A3 and A4.

VAC would be the abbreviation of Volt Altern Current which would be translated Volts of alternating current. The difference between VDC is that its sinusoidal oscillation achieving a more efficient energy transmission.

The alternating current is the energy that we receive in our homes, it is generated in the power plants by means of alternators.

The intensity of this type of current varies with time, and changes direction 50 times throughsecond (50hz). The generated voltage changes in the form of sine wave so it is not constant.

In the image:

1. Current by pulsations.
2. Direct current (DC).
3. Alternating current (AC).
4. Variable current.