Closed circuit television, or CCTV (stands for closed circuit television) surveillance is a technology designed to monitor a variety of environments and activities. It is called closed, that, contrary to what happens with the media, all components are linked. In addition, unlike conventional television, this is a security system designed to

VDC would be the abbreviation for Volt Direct Current which translated would volts direct current. The idea of ??this type is unidirectional current to the load. Direct current is normally produced by batteries, thermocouples, solar cells and a dynamo electric machine type. The direct current can flow in conductors such as wires, but may also flow through semiconductors, insulators ... In the image: 1 - current per pulse 2 - Direct Current (DC) 3 - Alternating Current (AC) 4 - Variable Current

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.

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).