Author: Voltmatic Trading

  • Network Switches

    Network Switches

    A network switch—not to be confused with a light switch or a Nintendo Switch—is a box that you connect to your home router to gain more Ethernet ports. Think of it as functioning like a USB hub but for networking.

    Because home routers usually come with three or four Ethernet ports built in, and because almost everything on a home network—laptops, phones, game consoles, streaming boxes, and smart-home accessories—uses Wi-Fi anyway, most people don’t need a network switch. But a switch is useful if your router doesn’t have enough Ethernet ports (like the Eero mesh router, which has only one port free after you’ve connected your modem), if you have a lot of wired devices in one place (such as in an entertainment center), if you’re trying to use wires to improve your speeds or cut down on wireless interference, or if you’re installing Ethernet ports in your home’s walls.

    For adding a few more ports
    The most common kind of switch, at least for homes and small businesses, is called an unmanaged switch. That means the switch itself has no settings or special features, and it exists only to add more Ethernet ports to your network. Your router continues to handle your Internet connection, letting your devices talk to one another and restricting what certain devices can do through parental controls or other settings—the switch is effectively invisible. In contrast, the kinds of things that managed switches do—such as monitoring traffic on individual ports or setting up virtual networks (VLANs) using the same switch—are really important only for large corporate networks.

    Because unmanaged switches are so simple, models from different manufacturers all perform about the same. Simply find a Gigabit Ethernet switch with the number of ports you need from a reputable networking company like D-Link, Netgear, TP-Link, or TrendNet, make sure the owner reviews aren’t awful (both of the models we like have 4.5 stars out of five across hundreds of reviews at this writing), and buy that one. A good five-port switch, such as this one from TP-Link—with one port to connect to an Ethernet port on your router, and four to connect to your devices—should cost $20 or less. An eight-port switch should cost no more than $30. These options are well-reviewed and inexpensive, but they certainly aren’t the only good choices.

    For adding Ethernet all over your house
    A good mesh-networking kit saves you from needing to run Ethernet cabling through your walls no matter how big or complicated your house is, and it’s usually cheaper too. But if you want fast, lag-free connections in every room of your house—if you play online games, stream 4K video from a local server, or transfer large files over your network every day—there’s still no substitute for wired Ethernet.

    A switch is just one part of a home wiring project, and you should read a full how-to guide before you decide whether this is something you want to try, even if you plan on hiring a contractor to do the actual wiring. Putting Ethernet cables in walls has become less appealing (and less necessary) as Wi-Fi has improved, and it might not even be an option for people who rent their apartment or home (though in that case you could still run wires along the baseboards if having cables out in the open doesn’t bother you).

    Decide how many rooms you’d like to wire up and how many Ethernet jacks you’d like in each room, and then buy a switch with at least that many ports; we recommend getting a few more ports than you need in case you want to wire up more later, or in case a port on the switch dies over the course of its life. A 16-port unmanaged switch such as this one from TP-Link should run you $50 or $60, while a 24-port unmanaged switch like this one from Netgear typically costs between $70 and $90. Both options are from reliable manufacturers, have decent reviews, and are reasonably priced.

    Here’s what to look for in wiring your home:

    Pick a place where the switch will live: This spot should be out of view—larger switches are big, ugly boxes you probably won’t want to have sitting on a shelf in the open—but easy to access for setup and troubleshooting. It should also be easy to run cables to, and it must be less than 100 meters (328 feet) from the farthest room you want to wire, since that’s the maximum length over which most Ethernet cables will reliably work.
    Get some cabling: Category 6 (or Cat 6) cabling hits the sweet spot of speed, price, and future-proofness.1 It can carry a 1-gigabit Ethernet signal for up to 100 meters and a 10-gigabit signal for up to 55 meters (10-gigabit Ethernet is still rare and expensive, a situation that’s unlikely to change soon). You can find lots of different kinds of Ethernet cables, distinguished by whether they are shielded from electromagnetic interference2 and what kind of coating they use. You should at least use “riser” (or CMR) cable, which is designed to be used vertically in walls to prevent fire from spreading from floor to floor in your home. “Plenum” (or CMP) cable is for horizontal runs; it’s more expensive but designed to stop fire from spreading more than 5 feet along the cable in any direction. A 1,000-foot roll of CMR cable costs about $90, while the same amount of CMP cable costs a little over twice as much.
    Get ready to cut some cables: Buy Ethernet plugs and strain-relief boots so that you can plug the cables into your switch after you’ve cut them with your wire stripper and crimping tool. This YouTube tutorial on cutting Ethernet cables is quick and clear.
    Get wall jacks: First, buy wall plates and mounting brackets for all the rooms you’re wiring up—you can easily find plates for as few as one or as many as 12 ports. Then, buy as many Ethernet keystone jacks as you need—they fit into the plate and are the part that you plug your computer or game console’s Ethernet cable into.
    Using wires to improve your Wi-Fi
    Once a good wired network is installed, it will improve your Wi-Fi performance by reducing the number of devices competing for wireless bandwidth. But if you have an especially large house or just want to improve wireless performance even more, Wi-Fi access points such as the Ubiquiti UniFi series can talk to one another over your home’s Ethernet wiring to make sure your devices connect to the access point that will provide the best speeds, evenly distributing your network’s load to increase throughput and lower latency. These devices entirely replace your existing Wi-Fi, but you’ll still need a router—you can either turn your current router’s Wi-Fi off and continue using it as a wired router or replace it with a wired-only router like something from Ubiquiti’s EdgeRouter series.

    If you plan to take this approach, you may also want a switch that supports Power over Ethernet like this well-priced, well-reviewed 16-port switch from Netgear.3 This feature removes the need for separate power adapters on those access points, giving your setup a cleaner, simpler look—connect your Wi-Fi access points to the PoE ports on the switch, and they will receive both power and data over a single cable. Alternatively, you can buy PoE injector adapters to add PoE to any switch—the result will look messier in your networking closet, but this method is cheaper.

    Footnotes

    1. Cat 6 is not to be confused with the less-common Cat 6e, which can run a 10-gigabit Ethernet signal over 100 meters of cable but doesn’t matter for 1-gigabit Ethernet. Cat 6 is the best choice for home wiring projects as of early 2018. Most how-tos on wiring your home for Ethernet are a few years old—they’re still useful for planning purposes, but they may recommend older cables or switches if they haven’t been updated.
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    2. Your home will almost certainly be fine with unshielded cabling. Shielded cabling is more common in industrial spaces, where there’s a whole lot of power and other stuff already flowing behind the walls.
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    3. You can get smaller, five- and eight-port switches with PoE as well, but they cost three or four times as much as switches without PoE. Don’t buy one unless you need it.
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  • LED Lighting Fixture

    The light-emitting diode (LED) is one of today’s most energy-efficient and rapidly-developing lighting technologies. Quality LED light bulbs last longer, are more durable, and offer comparable or better light quality than other types of lighting. Check out the top 8 things you didn’t know about LEDs to learn more.

    Energy Savings
    LED is a highly energy efficient lighting technology, and has the potential to fundamentally change the future of lighting in the United States. Residential LEDs — especially ENERGY STAR rated products — use at least 75% less energy, and last 25 times longer, than incandescent lighting.

    Widespread use of LED lighting has the greatest potential impact on energy savings in the United States. By 2027, widespread use of LEDs could save about 348 TWh (compared to no LED use) of electricity: This is the equivalent annual electrical output of 44 large electric power plants (1000 megawatts each), and a total savings of more than $30 billion at today’s electricity prices.

    Learn more about how energy-efficient lightbulbs compare with traditional incandescents.

    How LEDs are Different
    LED lighting is very different from other lighting sources such as incandescent bulbs and CFLs. Key differences include the following:

    Light Source: LEDs are the size of a fleck of pepper, and a mix of red, green, and blue LEDs is typically used to make white light.
    Direction: LEDs emit light in a specific direction, reducing the need for reflectors and diffusers that can trap light. This feature makes LEDs more efficient for many uses such as recessed downlights and task lighting. With other types of lighting, the light must be reflected to the desired direction and more than half of the light may never leave the fixture.
    Heat: LEDs emit very little heat. In comparison, incandescent bulbs release 90% of their energy as heat and CFLs release about 80% of their energy as heat.
    LED Products
    LED lighting is currently available in a wide variety of home and industrial products, and the list is growing every year. The rapid development of LED technology leads to more products and improved manufacturing efficiency, which also results in lower prices. Below are some of the most common types of LED products.

    Industrial and Commercial Lighting

    The high efficiency and directional nature of LEDs makes them ideal for many industrial uses. LEDs are increasingly common in street lights, parking garage lighting, walkway and other outdoor area lighting, refrigerated case lighting, modular lighting, and task lighting.

    Kitchen Under-Cabinet Lighting

    Because LEDs are small and directional, they are ideal for lighting countertops for cooking and reading recipes. The color can appear more cool or blue than is typically desirable in a kitchen, and there can be some excessive shadowing in some fixtures, so it is important to compare products to find the best fixture for your space.

    Recessed Downlights

    Recessed downlights are commonly used in residential kitchens, hallways, and bathrooms, and in a number of office and commercial settings. DOE estimates there are at least 500 million recessed downlights installed in U.S. homes, and more than 20 million are sold each year. Both CFL and LED technology can decrease downlight wattage by 75% or more.

    LED Replacement Bulbs
    With performance improvements and dropping prices, LED lamps can replace 40, 60, and even 75 Watt incandescent bulbs. It’s important to read the Lighting Facts Label to make sure the product is the right brightness and color for the intended location. When chosen carefully, LED replacement products can be an excellent option.

    LED Holiday Lights

    LEDs consume far less electricity than incandescent bulbs, and decorative LED light strings such as Christmas tree lights are no different. Not only do LED holiday lights consume less electricity, they also have the following advantages:

    Safer: LEDs are much cooler than incandescent lights, reducing the risk of combustion or burnt fingers.
    Sturdier: LEDs are made with epoxy lenses, not glass, and are much more resistant to breakage.
    Longer lasting: The same LED string could still be in use 40 holiday seasons from now.
    Easier to install: Up to 25 strings of LEDs can be connected end-to-end without overloading a wall socket.
    Estimated cost of electricity to light a six-foot tree for 12 hours a day for 40 days

    TYPE OF LIGHT COST
    Incandescent C-9 lights $10.00
    LED C-9 lights $0.27
    Incandescent Mini-lights $2.74
    LED Mini-lights $0.82
    Estimated cost* of buying and operating lights for 10 holiday seasons

    Type of Light Cost
    Incandescent C-9 lights $122.19
    LED C-9 lights $17.99
    Incandescent Mini-lights $55.62
    LED Mini-lights $33.29
    *Assumes 50 C-9 bulbs and 200 mini-lights per tree, with electricity at $0.119 per kilowatt-hour (kWh) (AEO 2012 Residential Average). Prices of lights based on quoted prices for low volume purchases from major home improvement retailers. All costs have been discounted at an annual rate of 5.6%. Life span assumed to be three seasons (1,500 hours) for non-LED lights.

  • Fire Fighting Equipment

    Fire Fighting Equipment

    technical equipment designed to rescue people and protect valuable goods and natural resources from fire. The basic apparatus are fire trucks, fire-fighting trains, fireboats, and fire-fighting airplanes and helicopters. Fire-fighting equipment also includes fixed fire-extinguishing and fire-alarm systems, fire extinguishers, fire hydrants, and other means for conveying fire-extinguishing agents to the scene of a fire.

    The first attempts to develop fire-fighting equipment date from remote antiquity. Even before the Common Era, the Greek engineer and inventor Ctesibius constructed a fire engine that the Roman architect Vitruvius described as being able to shoot water upward. The engine was constructed with a water-flow fire pipe, that is, a reciprocating two-cylinder pump. Ctesibius’ invention was forgotten, however, and it was not until the 16th century that the goldsmith Anton Platner constructed a similar manual fire pump in Augsburg, Germany; the pump could send a jet of water 6 to 8 m. In 1672 in Amsterdam the Dutch inventor Jan van der Geide equipped a pump with an extensible hose; this made the pump the major tool in fire fighting. Water-flow fire pipes came into use in Russia in the 17th century; these were manual reciprocating pumps consisting of a pipe with a nozzle. The pipes were made of sheet copper or wood and were sometimes more than an arshin—some 70 cm—in length.

    After the invention of the steam engine, the first steam-driven fire pump was constructed in London in 1829. The pump was transported on horse-drawn wagons. Steam-driven fire pumps, which were introduced into Russia in 1862, could pump between 1,000 and 2,000 liters per min for up to 40 m. Pumps were first produced in Moscow in 1896. Although the newly invented steam automobile replaced the horse-drawn wagon, it was heavy and inconvenient; raising the steam pressure took between 10 and 15 min.

    Motor vehicles with internal-combustion engines were first used in fire fighting to carry firemen. In 1892 in Germany the first motor vehicle equipped with a mechanical fire pump was produced, and in 1907 the first mechanized fire ladder mounted on a motor vehicle. The motor vehicle radically changed the tactics used in extinguishing fires: it expanded the area served by fire-fighting stations, reduced the amount of time needed to reach a fire, and permitted mechanization of labor-intensive fire-fighting operations. In Russia, the first motor vehicle to carry firemen was used by the Moscow Fire Department in 1907. It was produced in Moscow at the Gustav List plant and could travel some 60 km/hr. It carried a crew of eight, as well as tools, ladders, and fire hoses. Fire trucks were subsequently acquired by the fire departments of St. Petersburg (Obukhov Factory), Riga, Arkhangel’sk (commercial port), and Kazan. In prerevolutionary Russia, however, the fire truck was not common, and there were just over ten such vehicles before 1917.

    Although water was long the major fire-extinguishing agent, it was not effective in a number of situations, for example, when oils and petroleum were burning. In the early 20th century, A. G. Loran, an instructor at a Gymnasium in Baku, proposed a new fire-extinguishing agent—chemical foam generated in fire extinguishers. The foam fire extinguisher, which Loran patented in 1902, used the chemical reaction of basic and acidic solutions as the basis for its action.

    During the first months of Soviet power in the USSR, great emphasis was placed on the development of fire-fighting equipment. The production of foaming agents, foam powders, and various foam devices got under way, and series production of fire trucks began in 1928. The USSR has pioneered the development of the technology and methods used to extinguish burning gas and petroleum gushers by means of explosives; the technique has found wide use throughout the world. In 1967 the USSR began using devices that extinguish gas and petroleum gushers by means of a mixture of exhaust gases from turbojet engines and water vapor.

    Fire-fighting equipment in the USSR is being developed with an eye to mechanizing fire-fighting operations. Equipment is being developed to make use of highly effective fire-extinguishing agents and make the work of firemen as easy and safe as possible. Fast-response stationary automated systems are being created and introduced to discover and extinguish fires at their onset.

    Special types of fire-fighting equipment have been introduced to safeguard airports and petroleum-refining, petrochemical, and chemical plants. The equipment uses highly effective fire-extinguishing compounds based on halogenated hydrocarbons, as well as inert gases, powders, moderately expanding foam, and finely dispersed water (fog).

    Industrial production has begun for fire tankers, truck-mounted pumps, waterworks, special-service automobiles, and water-foam apparatus. A heavy-duty fire truck now produced for airport service can pump 60 liters per sec and has a turntable monitor, a water-foam device, and a tank capacity of 11,000 liters; the truck permits rescue operations and extinction of any type of airplane fire. Special types of fire-fighting equipment produced for use in the northern USSR allow fires to be fought at atmospheric temperatures ranging from —50° to 35°C. New equipment has been introduced to fight fires in ports, petroleum storage areas, railroad yards, forests, and peat plants and on offshore petroleum rigs. Airplanes and helicopters are used to combat forest fires. Fireboats of the General Gamidov type may be used on offshore petroleum rigs under any weather conditions.

    Outside the USSR, the German Democratic Republic and Czechoslovakia have assumed leading positions in the production of fire-fighting equipment. The Metz and Magirus plants in the Federal Republic of Germany and the Angus, Dennis, and Simon plants in Great Britain have long experience in the production of fire ladders, fire trucks, and motor-driven pumps. The 30-m fire ladder produced by Metz, which is mounted on a special Faun chassis, is light, maneuvers well, and has good handling features. Simon produces a crank hoist mounted on a rotating platform.