Brian, you might be tempted to run a couple of small NE2 colon bulbs in series, but you will probably find that their combined strike voltage is higher than your HT power supply - either straight away, or after a few months of bedding in. They just stop working! So, run the neons (each with their own series resistor) in parallel.
These little NE2's are cheap, and prone to flicker. So buy a few spares, and run them in for a few days on your test bench at (say) 0.5mA each, and watch how they perform. Then select the best, stable ones. As John points out, only the cathode electrode will glow, so you might like to think about mounting/twisting the neon lamp so that the cathode faces "forwards" towards the viewer. Small point, but you'll see what I mean when you fire one up. Resistor values? Let's assume you've got 180V HT, and I'll go with John's maintain voltage of about 67V. So the resistor needs to drop the other 113V. Aim for about 0.5mA current initially, so according to Mr Ohm that's 226K, or 220K nearest E12 preferred value. That's your starting point, but don't be afraid to experiment with values between 47K (bright!) and 680K. The idea is to match the NE2 brightness in with your Nixies, so that the little fellas are not shouting "look at me!" all the time. I might also suggest... that you strap one NE2 and accompanying series resistor straight across your HT power supply, on the PCB, and close to the "hot" stuff". This will confirm and remind you whenever the HT is up and running, and just might prevent you sticking your finger where you shouldn't, just when you shouldn't! Listen to the voice of experience... :( And have fun :) On Dec 27, 11:54 pm, John Rehwinkel <jreh...@mac.com> wrote: > > Anyway, I'd like to use two neon lamps to display the colon between > > hours and minutes; do any of you have any suggestions for a lamp/tube > > that runs on a similar voltage as the nixies? > > Ordinary NE-2 bulbs seem to maintain at 67 volts or so, so a pair of 'em will > generally run cheerfully > from a nixie supply. You can also run them individually, with larger current > limiting resistors. > > Running 'em on DC will only have one of the electrodes glow, which may or may > not matter to you. > There are various schemes to switch the power at a high frequency (so both > electrodes appear lit) > or a low frequency (so the colons dance at 1Hz or so). > > - Welcome aboard, > John -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
