At 4:48 AM +0000 1/4/10, cagamba wrote:
--- In NEONIXIE-L@..., David Forbes <dforbes@...> wrote:
A 4.7K resistor in series with a 50K pot would be just fine.
Thanks everyone who chipped in, I'll try not to fry any tubes. ;)
So... under this arrangement (resistor+pot) I should start with the lower current and, measuring the voltage across the lit nixie, bring it up to the specified voltage? Is that it?
Another question, what's the difference between supply and maintaining voltage, present in nixies' specs? And which one should I use...?
The striking voltage is what starts the current flowing. It's often rated at 170V, but will increase in the dark, or in the cold, or with age of the tube. Not much current flows at this voltage, since the tube drops to the maintaining voltage as soon as it strikes. you design the power supply to provide more than this voltage.
I usually use 190V. 180V is a minimum for reliable operation. The higher your power supply voltage, the more power you waste in the resistor, but the longer the tubes will operate in years.
The maintaining voltage (~140V) is what keeps the gas ionized once it's already ionized. This is what you design the anode resistor to drop the voltage to at the rated current.
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--David Forbes, Tucson, AZ
