Ebook Interior lighting for designers (Fourth edition): Phần 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Interior lighting for designers (Fourth edition): Phần 2
Ebook Interior lighting for designers (Fourth edition): Phần 2
ElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumpt Ebook Interior lighting for designers (Fourth edition): Phần 2tion, operating costs, switch control, and dimming control.PRINCIPLES OF ELECTRICITYElecưically charged particles called electrons, which orbit the nucleus of an atom, can be made to flow from one point to another. This is observable in objects charged by friction and in natural phenomena: lightning Ebook Interior lighting for designers (Fourth edition): Phần 2 is a huge sparfc of electricity.A flow of elecưicity is called an electric current: the rate of flow of an electric current is measured in amperes (aEbook Interior lighting for designers (Fourth edition): Phần 2
mps, A). The potential of the flow of electncity is called voltage: it IS measured in units called volts (V).Water provides a helpful analogy to theseElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumpt Ebook Interior lighting for designers (Fourth edition): Phần 2ement, the rate at which water passes through the pipe. The pipe is the conductor or wire, the wall of the pipe is the insulator, and the faucet is the resistance or dimmer. The larger the pipe, the greater the flow it can carry.The path through which an electric current flows is called a circuit. W Ebook Interior lighting for designers (Fourth edition): Phần 2hen no gap exists in the path, it is called a complete circuit (figure 11.1). When a gap occurs, it is called a break in the circuit.Resistance impedeEbook Interior lighting for designers (Fourth edition): Phần 2
s the flow of current and IS determined by the composition of a material. This results in the production of light or heat or both. A resistor is a devElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumpt Ebook Interior lighting for designers (Fourth edition): Phần 2LIGHTING FOR DESIGNERSresistance or interrupted by an open switch, there will be little or no current (amps) even though the potential to produce it (volts) is high.WiringMaterials that electricity flows easily through are called conductors. Materials through which it does not flow easily are called Ebook Interior lighting for designers (Fourth edition): Phần 2 poor conductors, or insulators. All metals are good conductors: silver is the best conductor, but it Is too costly for most wiring purposes: copper IEbook Interior lighting for designers (Fourth edition): Phần 2
S an excellent conductor and is used widely.Almost all wire is encased within an insulator, which confines the current to Its metallic conductor. WireElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumpt Ebook Interior lighting for designers (Fourth edition): Phần 2e, the wrapping is removed from the ends of the wire.Insulated circuit wires are sometimes covered by a mechanically protective conduit for installation in buildings. Flexible, nonmetalhc sheathed cable (“romex") and flexible, metal sheathed cable ("BX") are often used in single-family homes. Commer Ebook Interior lighting for designers (Fourth edition): Phần 2cial installations use wires inserted in flexible metal conduit ("greenfield’’), or in rigid elec-tncal metal tubing (“EMT") for long runs.CircuitsDirEbook Interior lighting for designers (Fourth edition): Phần 2
ect current (de) is electric current that always flows in one direction. Alternating cuưent (ac) also moves in a single direction: however, that direcElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumpt Ebook Interior lighting for designers (Fourth edition): Phần 2te set of values through which the alternating current passes. The unit Hertz (Hz) Is used to measure the number of times the cycle occurs each second, which is also called the frequency of the cycle. Power distnbution sys-tems operate at 60 Hz in the United States and 50 Hz in most other parts of t Ebook Interior lighting for designers (Fourth edition): Phần 2he world.Series circuitIf one lamp fails in an inexpensive strand of Christmas tree lights, the remaining lamps in the strand go out. When the tungsteEbook Interior lighting for designers (Fourth edition): Phần 2
n wire in one lamp breaks, it causes a break in the circuit because its filament is part of the conductive path carrying current to other lamps.lamps ElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumpt Ebook Interior lighting for designers (Fourth edition): Phần 2e remaining lamps will grow brighter or dimmer due to the substituted lamp's resistance. A series circuit IS therefore said to be load-sensitive (figure 11.3).Parallel circuitIf one lamp in figure 11.4 goes off, all of the others remain lighted: the current still flows to the other lamps and the cir Ebook Interior lighting for designers (Fourth edition): Phần 2cuit remains complete. These lamps are wired in parallel. Since the voltage of the circuit IS present across all branches of the circuit, several diffEbook Interior lighting for designers (Fourth edition): Phần 2
erent loads (for example, a 60 W lamp and a 100 W lamp) may be connected to the136ELECTRICITYFigure 11.4 Parallel circuit.same circuit. Parallel circuElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumpt Ebook Interior lighting for designers (Fourth edition): Phần 2uch each other, the current will pass from one to the other because this is a shorter and easier path than the one intended: there will be a short circuit.In the drawing on the left in figure 11.5, the current will take a shortcut back to the cell without going through the push button: the bell will Ebook Interior lighting for designers (Fourth edition): Phần 2 ring continuously whether the switch is open or closed. In the drawing on the right, the bell will not ring at all: the current will take a shortcutEbook Interior lighting for designers (Fourth edition): Phần 2
back to the cell without going through the bell.A short circuit allovzs a stronger-than-usual flow of electricity through the wires: this excessive cuElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumpt Ebook Interior lighting for designers (Fourth edition): Phần 2 the fuse is part of the circuit, it also overheats and a metal strip in the fuse melts and breaks the circuit. If the protective device is a circuit breaker, the excess current of the short circuit causes the breaker to flip open, interrupting the path of the current.Figure 11.5 Two short circuits. Ebook Interior lighting for designers (Fourth edition): Phần 2 The wire in these circuits cs bare wire. Where the wires are twisted together, the current would flow from one to the other.137INTERIOR LIGHTING FOREbook Interior lighting for designers (Fourth edition): Phần 2
DESIGNERSElectrical DistributionElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumptElectricityKnowledge of the basic principles of electricity is necessary for understanding lighting circuitry, electrical distribution, power consumptGọi ngay
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