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A preheat fluorescent lamp circuit using automatic starting switch. A: Fluorescent tube, B: Power (+220 volts), C: Starter, D: Switch (bi-metallic thermostat), E: Capacitor, F: Filaments, G: Ballast. When power is first applied to the circuit, there will be a glow discharge across the electrodes in the starter lamp.
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, to produce ultraviolet and make a phosphor coating in the lamp glow.
[1] [3] To prevent this, fluorescent tubes are connected to the power line through a ballast. The ballast adds positive impedance (AC resistance) to the circuit to counteract the negative resistance of the tube, limiting the current. [1] Several American magnetic ballasts for fluorescent lamps. The top is a rapid start series autoregulator ...
In the 1970s, 34-watt energy-saving F40T12 fluorescent lamps were intoroduced in the United States. In the 1980s, T8 32-watt lamps were introduced, [8] but unlike the T8 tubes introduced in Europe, these T8s are not retrofits and require new matching ballasts to drive them. These ballasts were originally magnetic, but most today are electronic.
The ballast is wired in series with the lamp and performs two functions. First, when the power is first switched on, the igniter/starter (which is wired in parallel across the lamp) sets up a small current through the ballast and starter. This creates a small magnetic field within the ballast windings.
A General Electric NE-34 glow lamp, manufactured circa 1930. Neon was discovered in 1898 by William Ramsay and Morris Travers.The characteristic, brilliant red color that is emitted by gaseous neon when excited electrically was noted immediately; Travers later wrote, "the blaze of crimson light from the tube told its own story and was a sight to dwell upon and never forget."
A hallway under regular lighting (left) and emergency lighting (right) US-style emergency lighting fixture An emergency light is a battery-backed lighting device that switches on automatically when a building experiences a power outage.
Fluorescent penetrant inspection (FPI) is a type of dye penetrant inspection in which a fluorescent dye is applied to the surface of a non-porous material in order to detect defects that may compromise the integrity or quality of the part in question. FPI is noted for its low cost and simple process, and is used widely in a variety of industries.