Incandescent Lamp
A lamp is a device that produces light by using electricity to heat a filament or gas inside a glass or quartz bulb. Different sized and shaped lamps can be used for a broad range of tasks, such as general room illumination or accentuating a particular spot or object.
Lamp's are Mainly three type
1⇒ Incandescent
ii) Gas Filled
2⇒ Gaseous Discharge
Incandescent Lamp
Regular Filament:
⇛ At high temperatures, both heat and light are generated.
⇛ The amount of light emission will increase with temperature.
⇛ Regular candles and fire are other instances of incandescent lamps.
⇛ Heat and, at higher temperatures, a little light are produced when an electric current is run through a metallic cable.
⇛ Radiant Efficiency is the proportion of light output to total radiant energy.
⇛ Thomas Alva Edison, inventor of the first electric lamp .
⇛ The carbon filament was used in the first light.
⇛ Porcelain globe that has been fully emptied .
⇛ Filament, which is the fine filament inside the glass globe;
⇛ Cement, which is the powder-filled cap.
Why was we evacuated?
Filament Material
Required Properties :
(a) strong resistivity is . i.e. ρ
(b) a high freezing point
(c) a low temperature coefficient of resistance,
(d) ductility,
(e) enough mechanical power .
Why not Carbon ?
Why Tungsten ?
Gas Filled Lamp
Coiled Coil Structure of Filament
Constructional Features
Constructional Features |