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Not so Nomad. Check out the datasheet for the old NE-38S here: https://www.mouser.com/datasheet/2/423/NeonLampsRev3-1222934.pdf The specified current to light this neon indicator is only 300 microamps. The 90 volt drop is insignificant when dealing with the high voltage associated with this tester.

I also wouldn't place any resistor in parallel with the neon light because that would reduce its sensitivity and still not provide a fixed current limitation to the bulb. That's where I would place a Zener in parallel with the bulb, with a voltage just above the point where it lights. That would protect the bulb regardless of the voltage setting or leakage current, without increasing the current required to light it.

[QUOTE="Shockwave, post: 763274, member: 10882"] Not so Nomad. Check out the datasheet for the old NE-38S here: [URL]https://www.mouser.com/datasheet/2/423/NeonLampsRev3-1222934.pdf[/URL] The specified current to light this neon indicator is only 300 microamps. The 90 volt drop is insignificant when dealing with the high voltage associated with this tester. I also wouldn't place any resistor in parallel with the neon light because that would reduce its sensitivity and still not provide a fixed current limitation to the bulb. That's where I would place a Zener in parallel with the bulb, with a voltage just above the point where it lights. That would protect the bulb regardless of the voltage setting or leakage current, without increasing the current required to light it. [/QUOTE]

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