What Is Tungsten Filament Lamps And Fluorescent Tubes

July 23, 2020February 25, 2022 CS Electrical And Electronics

Hello Guys, welcome back to my blog. In this article, I will discuss what is tungsten filament lamps and fluorescent tubes, the difference between them, I will also discuss about difference between tungsten filament and fluorescent tubes.

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Tungsten Filament Lamps And Fluorescent Tubes

What is Tungsten Filament Lamps?

Filament Lamp – When an electric current is passed through a fine metallic wire, heat is produced and the temperature of the wire increases. At low temperature, the wire radiates heat energy, as the temperature of the wire increases due to heating it radiates heat as well as light energy.

The higher the temperature of the wire, the higher is the amount of light energy radiated. A black body when heated at 6250 degrees C emits the maximum energy in the visible spectrum range.

The incandescent or filament type lamp consists of a glass globe as shown in the above figure completely evacuated and a wire, called a filament, within it. The glass globe is evacuated to prevent the oxidation and convection currents of the filament and also to prevent the temperature being lowered by radiation.

The material, which can be used for the filaments of incandescent lamps, must possess the properties of high melting point, high resistivity, low-temperature coefficient, ductility, low vapor pressure, etc.

The material used in filament lamps is normally tungsten, carbon, tantalum, and osmium.

Carbon filament has a melting point of 3,500 degrees C, but it has many drawbacks i.e., resistance will decrease as temperature increases and it will draw more current from mains

Osmium is also a filament but it is very rarely used and the cost of this metal is very expensive. The melting point of the osmium melt is 2,600 degrees C.

Tantalum – It has a melting point of 2,800 degrees C only and it can not be operated at a higher temperature to give good efficiency.

Tungsten – Tungsten is also a filament, nowadays in every filament lamps, tungsten melt is used because it has many advantages like high melting point, high resistivity, mechanically strong, etc.

What are Fluorescent Tubers?

Fluorescent Tubes has many advantages compared to filament lamps. The fluorescent tube will also emit light when supply is given to it. The tubes can be obtained at a different size.

Fluorescent Tubes with wattage and length.

01. 38 cm long tube has 14 watts.
02. 46 cm long tube has 15 watts.
03. A 61 cm length tube has 20 watts.
04. 100 cm long tube has 25 watts.
05. 122 cm long tube has 40 watts.
06. 152 cm long tube has 65 watts.
07. 152 cm long tube has 80 watts.

The fluorescent tube consists of a glass tube of the same diameter and length of the tubes as given above. The inside surface of glass i.e., a tube is coated by silicate, cadmium, etc. Those elements used for coating are called phosphors. The tube also contains a small quantity of argon gas at a pressure of 2.5 mm of mercury. The fluorescent tube also consists of two electrodes coated with electron emissive material.

A starting switch is provided in the circuit, which puts the electrode directly across the supply mains at the time of starting, so that electrodes may get heated and emit sufficient electrons. A stabilizing choke is connected in series with it, which acts as ballast in running condition and provides a voltage impulse for starting. A capacitor is connected across the circuit to improve the power factor.

Difference Between Tungsten Filament Lamps And Fluorescent Tubes

01. Voltage fluctuation has comparatively more effect on the light output in the case of filament lamps whereas in the case of fluorescent tubes voltage fluctuation has a comparatively low effect because in tube choke is present.

02. In the case of filament, luminous efficiency increases with the increase in voltage of the lamp whereas in the case of fluorescent tubes luminous efficiency increases with the increase in wattage and an increase in the length of tubes.

03. In the case of filament, it gives light close to natural light, therefore, objects are properly seen whereas in the case of fluorescent tubes it does not give light close to natural light, therefore, color rendering is defective.

04. In the case of filament, the luminous efficiency of colored filament lamps is poor because colored glasses are used for this purpose whereas, in the case of fluorescent tubes, different color lights can be obtained by using the different components of the fluorescent powder. Hence efficiency is high and better colors are obtained.

05. In the case of filament, due to comparatively high working temperature heat radiations are also present whereas in the case of tubes, due to low working temperature heat radiations are low.

06. In the case of filament, the brightness of the light is more whereas in tube brightness of the light is less.

07. In both cases, time light output will reduce.

08. The life of filament lamps varies with the working voltage, normally it has a life span of 1,000 working hours. The life span of the tube is 7,500 working hours.

09. The initial cost of both lights is low.

I hope this article may help you all a lot…..

Thank You For Reading…… Bye

Tags: What Is Tungsten Filament Lamps And Fluorescent Tubes, Difference Between Them, what is a filament, what is tungsten, what is osmium, what is carbon filament, the difference between filament and fluorescent tubes.

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