Abstract
As a filling gas of fluorescent lamps, argon, neon and their mixed gases are compared from various points of view.
For higher lamp input than a certain value, a mixture gas gives better luminous efficency than argon only and for much higher lamp input best efficiency is obtained with neon when compared under the condition of constant lamp length, but under the condition of constant lamp voltage argon is best and luminous efficiency becomes lower as neon percentage increases even for very high lamp input.
Because of larger cathode drop itself and of larger increase of it with the decrease of electron emissibity of cathode, there is a tendency of cathode destruction being more accelerated with neon percentage increased. This defect, however is to some extent improved by the external heating of cathode filament and in other words adequate external heating is indispensable for satisfactory performance when neon percentage is high.
