[time-nuts] GPS for Nixie Clock
jimlux
jimlux at earthlink.net
Sat Jul 16 09:44:24 EDT 2016
On 7/16/16 12:08 AM, John Swenson wrote:
> Yes, I was planning on using a high speed photo diode to actually
> measure the turn on time of the digits. I hadn't thought of the turn OFF
> time, do I want the old digit to be turned off before the new one lights
> up or for them to be overlapping? I have been thinking about what
> threshold to use, 50% intensity is probably about as good as any other.
> It might turn out that different digits turn on differently, so I will
> have to calibrate each one separately.
>
Looking at my 5326 nixie tube counter I would say that the capacitance
of the digits will be different: they're different areas and different
spacing from the grid in front. So I would expect the time constant on
the drive circuit to be (slightly) different. On the 5326, I believe
the drive circuit is lightbulbs and photoresistors (having not looked
inside in many years)
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