|
Date: |
|
Description: | The lamp is known as the Nernst patent lamp 'Auria' and is rated for 230 volts, 0.25 amps, being used on direct current only. The filament of this lamp is made from oxides of some of the rare metals and at ordinary temperatures is a non-conductor of electricity but when warmed up it becomes a conductor. A coiled resistance in the form of a flattened helic is located close to the filament and when the lamp is switched on it heats the filament until it conducts when the electricity passing still further increases the temperature until the filament emits a very intense light which requires screening by a semi-transparent globe. An iron ore wire resistance enclosed in a small glass bulb is a necessary addition. A small electro-magnet with a floating armature cuts out the heating resistance after the filament becomes luminous.
Part: bulb, Material: glass
image | Source: | Tyne & Wear Archives & Museums | Identifier: | emu.ecatalogue.science&industry.482380 | Go to resource |
|
|