A rack is a metal support designed to house electronic, computer and communications equipment. The measures for the width are normalized to be compatible with most equipment manufacturers. They are also called racks, cabinets, cabinets or closets. Each column has holes at regular intervals called U rack units (Pictured: 4) grouped in threes. The height (Pictured:5) of the racks is standardized and external dimensions of 200 mm by 200 mm. Being normal that from 4U to 46/47U height width types (Pictured: 7). Standard 600 mm or 800 mm Types of background (Pictured: 6) The depth of the frame is not standardized, as this flexibility is granted (Pictured: 8) to the equipment. The most common are: - 450 mm - 600 mm - 800 mm - 900 mm - 1000 mm - 1200 mm Type 19-inch rack can find various types of 19-inch rack. Rack Mural (Pictured: 2): Used to accommodate electronic network. They are the smallest and are anchored to wall. Rack Pie (Pictured: 1): They are used primarily for servers, UPS and network electronics. Open Rack (Pictured: 3): Open Rack Racks are available only modelsstructure, eliminating doors and other accessories.

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

There are several cabinet heights according to the needs of the installation, this height can be measured in rack units (U).

Each rack unit or U is the distance between each horizontal separation to place the different accessories inside the rack. This distance is 1.75 inches that is equal to 4.4445 cm high.

For example, if we say that a rack is 8U we will understand that it has 8 units to install device orAccessories of 4.44 cm in height.

Normally these accessories, like trays, guides, strips, etc. Occupy a unit of U (1U), but we can find that other devices or accessories occupy more units, for example can be a rack box to install a PC, a UPS, etc. It can be said that there is also a half unit of U (0.5U), in this case, two units could be installed in a rack unit.

As far as I knowEndo the units of rack that occupy the devices that we are going to install we will know the height that we need for our rack.

The size of the rack unit (U) is based on the standard specification for racks defined in EIA-310.

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).