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.

A DIN Rail is a metal rail of with standard size of 35 mm wide. (A)

It's commonly used on installation and assembly of electrical devices or controllers for home or business use.
Besides the typical DIN rail 35 mm x 7.5 mm, can also be found in other measures as:

- Mini DIN Rail, size 15 mm x 5.5 mm (B)
- DIN Rail, size 35 mm x 15 mm (C)
- G section, size 32 mm x 15 mm x 8mm (D)

These rails are designed for installations with a method of simple, fast and configurable fixing. Ideal for installation in electrical distribution points, distribution of telephone wiring, alarms, digital electric programmers, keystone adapter, attenuators and any other compatible device.

VDC would be the abbreviation for Volt Direct Current which translated would volts direct current. The idea of ??this type is unidirectional current to the load. Direct current is normally produced by batteries, thermocouples, solar cells and a dynamo electric machine type. The direct current can flow in conductors such as wires, but may also flow through semiconductors, insulators ... In the image: 1 - current per pulse 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.

AWG stands for "American Wire Gauge". It's used to represent measures of cable length and section.

This is an AWG conversion table:

AWG	Diam. mm	Area mm2		AWG	Diam. mm	Area mm2
1	7.35	42.40		16	1.29	1.31
2	6.54	33.60		17	1.15	1.04
3	5.86	27.00		18	1.024	0.823
4	5.19	21.20		19	0.912	0.653
5	4.62	16.80		20	0.812	0.519
6	4.11	13.30		21	0.723	0.412
7	3.67	10.60		22	0.644	0.325
8	3.26	8.35		23	0.573	0.259
9	2.91	6.62		24	0.511	0.205
10	2.59	5.27		25	0.455	0.163
11	2.30	4.15		26	0.405	0.128
12	2.05	3.31		27	0.361	0.102
13	1.83	2.63		28	0.321	0.0804
14	1.63	2.08		29	0.286	0.0646
15	1.45	1.65		30	0.255	0.0503