In , William Sommerwerck wrote:

Is 100 ohms a good value as a current-limiting resistor
for a small neon lamp running off 240V AC?

It is, if you want the neon lamp to light up whitish purple for less than an
second, then explode.

You need something more in the range of 150K to 200K, possibly even larger.

100 ohms in series with a neon lamp at 240 volts AC: Not that I would
try this for the answer, but I suspect both the neon lamp and the resistor
will likely be severely damaged. Either or both may explode, and the neon
lamp may implode.

- Don Klipstein )