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

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.

When calculating the life of a battery it will be necessary to know the number of charge cycles that can be performed until the battery does not begin to lose its capacity.
Depending on the type of battery these charging cycles can vary, the most common being the mobile batteries, manufactured Li-Ion or Li-Po, which have a duration of between 300 and 500 charging cycles according to model and manufacturer.
Once thisE limit we will notice how the battery loses duration of operation, arriving to lose up to 25% of its capacity of load.
At this point it will be necessary to evaluate a battery change.
It should be noted that usage and charging habits can significantly affect battery life. For example, factors such as heat, charge the battery several times a day without it is almost exhausted, etc. Will be affectedits duration.
Therefore, to get the most out of the battery we must know when a full charge cycle is performed, and try to avoid misuse of charge, to increase its useful life.
A charging cycle is considered when the battery has been discharged or its 100% charge has been used.
The manufacturers advise that the charge is never made below the 58% battery, since the battery voltage would not fall so lowTo, so you could end up winning up to 4000 charge cycles.
Tips to increase the life of a battery.

• Avoid extreme heat or cold or very long applications of the device.
• Charge the battery as often as you can.
• Fully discharge the battery from time to time.
• Do not let the battery run out completely before charging.

Below is a table with theDifferent voltages (V), charge cycles (C) and battery percentage (B).

One of the basic components in most electrical circuits or electrical installations are the fuses, the fuse is a capsule (B) that has metal ferrules (C) on its ends, in which a thin filament of alloy or metal (A) characterized by having a low melting point.
The fuse is placed in a specific point of the installation, and will serve to protect said installation frompossible damage due to electrical overload or voltage.
In their normal state the filaments have continuity at their ends (C, D). This over voltage causes this filament to heat up and break (C.1, C.2), not passing electrical energy and protecting the circuit while minimizing the risk of fire.

We can find all kinds of fuses, according to their amperage, design etc.
Among the most common we can findr:

• Cylindrical fuse glass material. They are usually used in most household appliances, power supplies, etc.
• Fuses for Blade vehicles. They are the fuses that protect the electrical installation of the vehicle, usually they are of the same type and design in most vehicles, according to their amperage they have a specific color.
• Brown = 5 A
• Red = 10 A
• Blue = 15 A
• Yellow= 20 A
• Colorless = 25 A
• Green = 30 A
• Fuses for mini vehicles: It is the same as the previous one but of a smaller size.
• Fuses for Maxi vehicles: It is the same as the previous one but of a larger size.
• Midi Fuses
• Mega Fuses
• Reed fuses
• High voltage or industrial fuses

Your symbol is represented as a box and a line that crossesA line or a line is a sinusoidal shape (E).