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 electrical mechanisms are indispensable in any installation of a house, office, etc. The mechanisms can be of several types depending on where the installation is performed.

• Recessed interior mechanisms: Ideal for indoor use.
• Mechanisms of interior in surface: Ideal for the use in interiors without necessity to realize work.
• Exterior mechanisms: Ideal for outdoor use andGarages

Within each type of installation is where we can find different mechanisms depending on the function we need. The most common electrical mechanisms in an electrical installation are:

1. Simple switch: The mechanism that serves to turn the light on or off at one point.
2. Switch: This is the same mechanism above, but this allows to turn the light on or off from two points diIngs.
3. Crossover switch: Same as above but allows turning off and on the light from three different points.
4. Pushbutton: Normally used for timbres or steps with light and on/off timer.
5. Regulator: It allows to control the level of power of light.
6. TV socket TDT/SAT: Connections for TV, radio, and/or satellite connection.
7. Base schuko: TomaCurrent based on neutral, line and ground.
8. Telephone or network socket: Bases for telecommunications, networks or telephone.