<P> Early lamps , and some small modern lamps used only a vacuum to protect the filament from oxygen . This however increases evaporation of the filament , albeit it eliminates the heat losses . </P>
<P> Early lamps , and some small modern lamps used only a vacuum to protect the filament from oxygen . This however increases evaporation of the filament , albeit it eliminates the heat losses . </P>
why does a light bulb need a vacuum
why does a light bulb need a vacuum
to protect the filament from oxygen
to protect the filament from oxygen