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)

The socket is the part that allows connecting the bulb to the socket. There is a wide selection of bushings for different types of bulbs. The nomenclature for each type includes 1 or more letters (type of lampholder), followed by 1 or more numbers (diameter of lampholder).
Example: The bush E27 would correspond to the type of thread E (Edison) of 27mm in diameter.

• E12: Diameter of 12mm, this is a tamYear smaller than the most commonly used standard E27.
• E14: It is the second most common cap, only varies a little of the E27, with a diameter of 14 to 17 mm. It is normally used for bulbs or lamps.
• E27: This is the most common cap. It has a thick cup shape with thread to be able to adapt to the connector. It measures 27mm wide.
• E40: Has a diameter of 40 mm, it is the largest thread of this tIpo.
• G4: With a distance between pins of 4.0 mm. It is a type of cap that is frequently used in appliqués, ceiling lamps and hanging lamps.
• G5.3: With a distance between pins of 5.33 mm. The GU 5.3 socket format is a format widely used in small led floodlights with transformer. Usually used in halogen lamps and dichroic halogens.
• GY6.35: With a distance between pins of 6.35 mm, trOf a model similar to the previous one.
• G9: With a ditancia between pins of 9,0 mm. Usually used for ceiling lamps and hanging lamps.
• G13: With a distance between pins of 12,7 mm. It is used in fluorescent tubes.
• GX53: With distance between pins of 53 mm. Its most common use is the installation in light bulbs to illuminate furniture or unusual places. It does not need transformer.
• GU10: With a distance between10 mm pins. The GU10 bushing shape is a widely used format in small transformerless LED spotlights. Usually used in dichroic halogen lamps.
• B22: Type of bayonet connector used in countries such as Africa, India and Ireland.
• MR16: Its use is normally limited to 12V halogen lamps.