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.

The DIN is a standard that was developed by the "Deutsches Institut für Normung" (one might call the national standards organization in Germany). The DIN is facing many sectors, but we have tried to focus on the DIN-oriented electronics and computing. In the case of Enclosures means qualifying under the German legislation on racks and is standardized to DIN 41494-7.