English: Poster of the Tungram Works about tungsten fillament with inert gas in Hungary in 1904. incorrect, see notes below
日付
1904. 1909 or later. Note: Date/Description incorrect. The brand name Tungsram was registered in 1909; in 1904 the company was known as EIVIRT. They began producing tungsten-filament bulbs in the end of 1906, and these were Just-Hanaman type bulbs with very different filament design. Inert gas filling came much later (nitrogen - 1913, krypton - 1930). This one could be an earlier carbon-filament bulb, as seen in this pic on the left
{{Information |Description ={{en|1=Poster of the Tungram Works about tungsten fillament with inert gas in Hungary in 1904. }} |Source ={{own}} |Author =Tungsram factory 1904 |Date =1904 |Permission =1904 |other_versions =