Well the upper electrode (the one closest to the base) technically doesn't need the ceramic insulation since the heat from the discharge keeps it hot. Universal burning lamps have both electrodes insulated so they can run in all positions.
[quote=TiCoune66]Well the upper electrode (the one closest to the base) technically doesn't need the ceramic insulation since the heat from the discharge keeps it hot. Universal burning lamps have both electrodes insulated so they can run in all positions.[/quote]
I see now
I see now