I think the best approach would be to increase the HV. If you look at the discussions of glow physics in Weston or Acton for example, the lag in striking a glow from dark (which is what we're talking about here) is reduced by using an anode voltage materially above the threshold striking voltage. Overdrive is a matter of tube current rather than anode voltage per se, so a simple compensatory tweak to the current-limiting resistor value will get you back to the same tube current as now. The cost of the change will be a little extra power dissipated in the current-limiting resistors, but that should be immaterial in most circumstances.
Jon. On Thursday, November 30, 2023 at 3:27:11 AM UTC gregebert wrote: > UV light source, such as from an LED ? > > On Wednesday, November 29, 2023 at 6:43:48 PM UTC-8 Jeff Walton wrote: > >> I've recently come across a situation where I have some tubes in a clock >> that are being directly driven and are having trouble starting when the >> room is darkened but light right up when a room light is turned on. These >> particular tubes were probably intended for use in a calculator. They are >> seven segment neon MG-17G tubes. Once the tubes have any of the segments >> lit, there is really no issue with the performance. It's when the tubes go >> completely dark if a space is used while scrolling a message or lighting a >> dash on and off to emulate a colon. I'm wondering if others have found any >> particular tricks to help convince tubes to light up. There is no >> "baselighting" and the HV is ~172v. I'm considering increasing the HV by >> 10-15v but don't want to over drive the tubes. Short of putting a >> radioactive source in the vicinity, are there other things that anyone has >> had any luck with? >> >> Jeff >> > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/ee14735e-1e40-4c6b-a815-77e670e1c89cn%40googlegroups.com.
