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 film speed sensitivity physically defined as the inverse of that required to attain a predetermined response input system. The scale was created for photographic emulsions but has also been adapted for electronic digital photography. In the one case as the other high sensitivity is the counterpart of loss of picture quality. The exposure index or senbility of a film is indicated by the scales ASA, DIN, ISO or GOST (Soviet scale currently unused). The ISO system is actually merging the ASA and DIN systems, because it indicates both values ??(so, for example, a film will have a sensitivity ISO 100/21).

We can find 3 types of jack connector, monaural TS connector (tip-sleeve), TRS (tip-ring-sleeve) and TRRS stereo plug (tip-ring-ring-sleeve) which is used in most mobile devices, tablets, MP3 etc ...
We can difference these 3 types of connectors according to their diameter:

1. 6.35 mm jack connector or TS.
2. 3.5mm minijack connector or TRS, is the most common, usually used in headphone's output of portable devices.
3. 2.5mm jack connector or TRRS.

It consists of a maximum of three connecting parts being called the largest mass or negative polarity and two smaller size located more towards the end of the connector,
The called positive that correspond to each channel, such three-part plug can transmit signals in two separate channels, also known as stereo signals. There's a mono version, consisting of only two parts, a negative and a positive.

A. Protector
B. Stem
C. Ring
D. Tip
E. Kindred
F. Ring (Signal Right)
G. Tip (Signal Left)

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.

ABS material (acrylonitrile butadiene styrene) is a type of thermoplastic that is very resistant to impact or shock.

Its applications are several, for example is a material widely used in the manufacture of interiors or components of cars such as moldings, as well as in products for domestic use such as toys, tools, housings of electrical devices etc.

One of its most important characteristics is its great tenacidad in almost all types of temperatures.

Being a very hard material has good chemical resistance, low water absorption and high resistance to abrasion, where other types of plastics would be more brittle.

This type of material is becoming very famous in the particular field and widely used due to the great growth in the sales of domestic 3D printers, the main printing raw material.next to the PLA.

Identification of ABS
Parts that are made of ABS material must be marked in accordance with ISO 11469 (DIN 58840).