you are superb and solved almost my queries but i want to know about harm caused by electrical wiring, i.e. electrical shock and other.
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Fuse is a term with several different meanings. In electronics, it prevents accidental overloads caused by electrical spikes. In hydraulics, the term is used for the device that prevents the unexpected loss of fluid pressure and is used to describe several different valve types. The word may also refer to a remote or delayed method of setting off explosives. In all three cases, the device is a safety mechanism that prevents injury to humans or devices.
Electric fuses are safety devices that will destroy themselves to prevent system overloads. In most cases, they will let an electric current move through it without interruption, but when a power spike travels into the system, they will overload the internal mechanism and burn out. This creates a break in the power flow and prevents the rest of the electricity from flowing into the system.
These types of fuses have many shapes and sizes, but they have a similar overall design. They have a single port where power flows in and a single port where it flows out. Each fuse governs one circuit, although a single circuit may break into multiple paths with different fuses after passing through the main system. When power flows through the system, the devices don’t cause any gain or loss in power. When the system overloads, a single line in each fuse melts or breaks, similar to a blown light bulb.
Hydraulic fuses are a catch-all term for a class of valves that keep the hydraulic pressure equalized inside a system. These valves often work via unexpected changes in pressure or the siphoning effects caused by moving liquid. If a system maintains a standard pressure, a valve may be set up to push against that pressure. Basically, it is always trying to close, but as long as the pressure is constant, it can’t do so. If the pressure drops, the valve can close and catch the remaining fluid before it escapes.
In addition, some valves work via suction. As water moves from one chamber to another, the valve is pulled shut by the moving water. In essence, the mechanical action is powered by the process it prevents. This valve is then held shut by the difference in pressure between the two chambers.
The last common type is used in explosives and fireworks. These fuses are methods of delaying an explosion long enough for a person to move a safe distance away from the blast area. For instance, if a person sets an explosive charge with a 30-second fuse, he will then have 30 seconds to move away from the area before the explosion goes off. These devices are less common in modern times, as more sophisticated remote-detonation methods are used, but they are still used in some common construction and mining practices.