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).

IEC connector is the common name for a set of thirteen power connectors (called the connector specifications) and thirteen outlet panels (called input) specification defined by IEC 60320 (formerly IEC 320) of the International Electrotechnical Commission ( IEC). When used without other qualifiers, "IEC connector" usually refers specifically to the C13 and C14 connectors.

The Bowens standard is a standard widely used in photography, mainly used for joining softbox or umbrella to any type of flash, notable for having 3-point hitch.

In IEC connector or cable with a base (usually plastic) and a plug to connect to the socket (plug), if we put these two things we would get the named SCHUKO is the overall connector. The schuko not determine the type of connector. It would be determined by the specification of the International Electrotechnical Commision (IEC). We leave a small sample of Schukos internationally.

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 photoelectric sensors are those sensors that act by closing or opening the circuit depending on the light intensity they receive.
The system consists of an emitter system in charge of emitting light and a receiver system, in charge of managing its function according to the light received.
We can find several types of photoelectric sensors although we can divide them into several more generic groups, barrier photocell (A), Self-reflective (B) and reflective with reflector (C).

The barrier sensor is possibly one of the most used sensors due to its simplicity of use, easy installation and reliable operation.
Its operation is simple, the transmitter is placed in line with the receiver being one in front of the other. Thanks to this distribution external aspects such as dirt, dust, humidity affect to a lesser extent its operation.
This type of barrier sensors have a range ofAnd much greater detection to the rest, it is possible to say that being an emitter and a receiver this type of sensors are not able to detect color in objects as other sensors can make and it is necessary to take into account that these sensors emit a light that is captured By the emitter, if when crossing the barrier we do with a transparent or translucent object will not be activated, as the beam of light will get through the object, therefore alone andS valid for objects with a high degree of opacity.
These types of sensors are widely used in security and automation systems, for example opening or closing a barrier or door, activating an alarm, etc.
When faced with, the emitter emits a beam of light to the receiver, if the receiver is receiving the light beam it will be in standby mode to act. When an object passes between the sender and the receiver, cutting the view directlyAnd leaving the receiver without receiving the light this will activate the function for which it is programmed, for example in a security door, the door remains closed while the light beam is received by the receiver, if a person passes between the two transmitters The beam and light will be interrupted by the body of the person, so that the sensor will act by opening the door.

This is one of the most economical models of detectors by photocell, but against is one of the least recommended in situations with high humidity or places with a lot of dust or dirt. The reception distance is also shortened as opposed to the barrier, so they do not have as much detection range. This factor is directly linked to the color of the object, since the light emitted must bounce on it, it will not haveThe same index of reflection an object of black color (that absorbs the light) to a white object (that bounces the light), therefore, objects of light colors will be better detected with a self-reflecting photocell.
This type of sensors unlike those of barrier, its emitter and receiver are in a single device. The emitter emits light on the object, when light reaches the object it bounces and is received by the receiver, qYou will be in charge of executing the action, like stopping a tape, adding a unit, triggering a mechanism, etc.
As it is a single device its installation is minimized, since it is only necessary to feed a point, unlike the barrier that are two points. They are ideal for installations where it is complicated or there is no space to place the receiving device.
This type of photocells can be divided into 3 groups,Standard or self-reflecting photocells, background suppression and autoreflective foreground photocells (FGS, Foreground suppression)

• Self-reflective or non-suppressed photocells (the standards) are those whose detection distance is affected by the color of the detected object. As a result of this small inconvenience,Have improved these sensors by creating two variants, with background suppression and foreground suppression.
• Self-reflective or suppressed photocells work in the same way as the previous ones, but also use several triangulations of the light to calculate the exact position in which the object is. Thanks to these triangulations the sensor is able to ignore any object that may be behind and pUeda interfere in the detection, in such a way that they are not so affected by lighter colors, shapes or brightness of the object.
• Self-reflective photocells with foreground suppression are those that work just like background suppression but focus on the background surface, adjusting the detection zone at that distance. Basically, what the sensor does is focus on the background and will detect any object thatIs placed on said background, for example, is the system used for the detection of objects on a conveyor belt or other surface.

two.

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.