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Sodium Vapour Lamp consists of a discharge tube created from a heat resistant glass, containing a modest quantity of metallic sodium, neon gas and two electrodes, Neon gas is added to start off the discharge and to develop sufficient heat to vaporize the sodium. Because of law pressure inside the tube, a sufficiently extended tube necessary to acquire a lot more light. To decrease the overall dimension of the lamp, this tube is generally bent into U-shape.

The light created by this lamp is yellowish which is created at its optimum pressure of about .004mm of mercury. This pressure is obtained at a temperature of about 280 C and so it becomes essential to sustain this temperature. For this objective the U-tube is enclosed in a double walled flask to avert lose of heat. The double walled flask is interchangeable and can be fitted on to one more U-tube. Whilst replacing the inner U-tube 1 have to be extremely cautious simply because if it is broken and sodium comes in get in touch with with moisture, it might result in fire.

All electric discharge lamps call for a higher voltage at the time of starting and low voltage for the duration of operation. Typically, 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 enough to begin the discharge. When the lamp is fully operative following 10 - 15 minutes, the voltage across it falls to about 150 volts. Since of the high reactance of circuit, the power factor is low and hence a p.f improvement capacitor is connected.

The efficiency of a low pressure sodium vapour lamp is very high (about 40 - 50 lumens/watt) and it produces a light of distinct wavelength possessing yellow color. Sodium lamps are primarily employed for street, high way and airfield lighting exactly where color distinction is not so required. blu cig review electric cigarette brands website electronic cigarette side effects