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Sodium Vapour Lamp consists of a discharge tube produced from a heat resistant glass, containing a little quantity of metallic sodium, neon gas and two electrodes, Neon gas is added to begin the discharge and to develop sufficient heat to vaporize the sodium. Due to the fact of law pressure inside the tube, a sufficiently lengthy tube needed to obtain much more light. To lessen the overall dimension of the lamp, this tube is generally bent into U-shape. The light made by this lamp is yellowish which is produced at its optimum pressure of about .004mm of mercury. This stress is obtained at a temperature of about 280 C and so it becomes necessary to preserve this temperature. For this goal the U-tube is enclosed in a double walled flask to avert shed of heat. The double walled flask is interchangeable and can be fitted on to another U-tube. Whilst replacing the inner U-tube a single should be very cautious due to the fact if it is broken and sodium comes in speak to with moisture, it could outcome in fire. All electric discharge lamps require a larger voltage at the time of starting and low voltage in the course of operation. Generally, sodium vapour lamps are operated by a high leakage reactance transformer. At starting a high voltage of about 450 volts is applied across the lamp which is adequate to start the discharge. When the lamp is totally operative following ten - 15 minutes, the voltage across it falls to about 150 volts. This refreshing  [http://www.xingrunit.com/what-is-tamoxifen.html crt peptides]  wiki has several original suggestions for where to acknowledge it. Since of the high reactance of circuit, the power element is low and hence a p.f improvement capacitor is connected. The efficiency of a low pressure sodium vapour lamp is extremely high (about 40 - 50 lumens/watt) and it produces a light of specific wavelength possessing yellow color. Sodium lamps are mostly employed for street, higher way and airfield lighting where color distinction is not so essential.