One hertz is one cycle per second, meaning repeating cycle as an event. For example, hertz is applied physics measuring the number of times for a second wave (either acoustic or electromagnetic) is repeated or can be applied, among other uses, to ocean waves that reach the Beach vibrations per second or a solid. The quantity that measures the frequency hertz is called,in this regard, the inverse of the period. One hertz is an oscillation frequency of suffering a particle over a period of one second.

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.

Meaning of the standard: Protection Devices Surge connected to low voltage electrical systems. Requirements and test methods.

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.

hen we talk about IP code (International Protection) we talk about an international standard (IEC 60529) which classifies the protection against external factors, solid or liquid, that has a component or electronic device; LED strips, controllers, meters, security cameras, etc.

This alpha-numerically standard has been designed to sort different levels of protection. Nomenclature starts with IP followed by two numeric values.

- Example IP68:

The first value ranges from 0 to 6 and indicates the protection against solid agents. In this case, strong protection against dust.

The second value is between 0 and 8 and indicates the protection against liquid agents. In this case the complete and prolonged immersion during the time specified by the manufacturer.

We could say that the larger the number is greater IP protection has a device.

In below table, we can see different IP protections levels available.

IPXX	First digit (IPxx)	Second digit (IPxx)
0	Unprotected.	Unprotected.
1	Protection against objects of> 50 mm diameter.	Protection against vertically dripping water.
2	Protection against objects of> 12.5 mm diameter.	Protection against inclined drip water up to 15°.
3	Protection against objects of> 2 mm in diameter.	Protection against water projected from any direction, up to 60°.
4	Protection against objects of> 1 mm in diameter.	Protection against splashing water any direction.
5	Ingress of dust is not entirely revented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment .	Protection against water jets.
6	Dust tight.	Protection against strong jets of water.
7		Protection against complete immersion up to 1 meter for 30 minutes.
8		Protection against complete and prolonged immersion.

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.