The lumen (symbol: lm) is the unit of the International System of Units to measure the luminous flux, a measure of the light power emitted by the source. The luminous flux of radiant flux difference that the former provides the variable sensitivity of the eye to different wavelengths of light and the latter involves all electromagnetic radiation emitted by the source according Wien law and Stefan-Boltzmann regardless of whether such radiation is visible or not. 1 lm = 1 cd. sr = 1 lx. m2

The use of LED bulbs has grown exponentially due to its great advantages. The LEDs are diodes that when passing the current emit light, these LEDs are controlled with a driver or power supply, providing a very stable power source and thanks to its dissipation system can achieve high performance and many hours of illumination .

• Duration of up to 50,000 hours, thanks to its dissipation system and voltControlled air.
• Fast on. The LED lights up much faster than a conventional light bulb.
• They do not emit almost heat, so they do not burn when touched.
• They contain no gas, no mercury, no pollutants.
• They consume 80% less than traditional light bulbs. Thanks to its continuous research, it is possible that this type of technology continues to evolve and reduce its consumption.
• LWhich emit, do not radiate ultraviolet or infrared rays.
• Low maintenance, since the LEDs do not melt, it only decreases its power. This dramatically lowers maintenance costs.
• Different shades, we can find different types of LEDs where we will find different shades of light, which can go from 2700K (yellow light) to 8000K (white light) without using filters.
• Sturdiness,If we compare with conventional light bulbs we find that LED technology withstands the vibrations much better. Ideal for what type of extreme installations.
• Emitting a direct light, the LED is characterized by being a directional light, so there is no loss of light.

L: Lumens
D: Duration in years
A: Saving
I: incandescent
H: Halogen
F: Fluorescent
D: Led Diode

Nowadays we all have in mind the importance of controlling and verifying the bills we receive in the stores. Thanks to the different security systems implemented and the renewal of protection systems in the new current tickets, it becomes increasingly difficult to falsify, but still an extra control is highly recommended.
Counting systems or banknote detectors use the combination of vArias detection technologies to check if the ticket is false or the ticket is true.
Among the detection systems we find from the simplest (pen) to machines that verify different characteristics of the ticket to verify their authenticity.
The most common detection systems are:

1. LABEL: Simply mark the ticket to check. If the mark is displayed in black, the billetAnd is false.

Detecting machines: The most reliable, as they can combine different detection technologies such as:

1. UV: Ultraviolet detection. It allows in a visual way to verify the markings integrated in the ticket with fluorescent phosphors that can not be seen in daylight and are only visible with an ultraviolet light at a certain frequency.
2. IR: Infrared light detection: Other systemOf safety implemented in the tickets is their ink, since under a type of infrared light they exhibit a special behavior. There are two types of ink, the ink that shines when exposed to an IR light and the ink that does the opposite and absorbs the light giving a black tone.
3. MG1 and MG2: This is the magnetic detection. The tickets incorporate a magnetic security system, which is based on a band usually on the sideOf the note, of a ferromagnetic material. This security system is not visible without the proper detector. Another safety system based on magnetic detection is to print the bill with areas of magnetic ink.
4. SIZE: It is based on the detection of the ticket checking its size in length and width. Each ticket has some special characteristics and very specific in terms of measurement, each one of them is fabriTo the millimeter.
5. DD: Thickness detection. Just as each ticket has an exact size, they also have a specific thickness.

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.

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.