Hey guys, so just as an experiment I took an old 1950s GE neon sign transformer rated at 9 kv@60 MA that I use for Jacob‘s ladders and stuff and simply use alligator clips to connect it to a T12. I put one clip across both left pins and one clip across both right. The bulb instantly started up and ran at what seems like, normal brightness. Then shut it down and that was the end of the story. What exactly is going on here and am I overdriving/underdriving or would it actually just work perfectly? My hunch is that a lot of wrong things are going on, but I can’t understand what. In my mind if a little than neon tube can take it I would assume it wouldn’t harm the bulb, but did not continue for more than about three seconds. Thanks so much for any info. It’s just pure curiosity.

What you were doing was running the tube with cold electrodes. Strongly not recommended as it said to kill the tube in just a few hours or even less. High open circuit voltage of neon transformer forces the discharge at whatever mode, cold or hot, but the current is limited at just 60mA or so. Brightness, for sure, was not near the normal, as the current was just below 1/7 of nominal.

Thank you, I appreciate that! That makes sense.