25 May
2005
25 May
'05
3:48 p.m.
I wrote:
You turn on a particular tube by dropping the X line
to 0V and raising
the Y line to +105V. The selected tube sees 105V, while the other tubes
in the same row and column see 97.5V.
Tom wrote:
I think your idea is generally right, but this detail
seems wrong:
when X goes from +7.5V to 0V, the entire line will see 105V,
striking the entire line.
Nope.
7.5V 0V
X0 X1
| |
| |
97.5V Y0 --------90V-----------97.5V
| |
| |
105.0V Y1 --------97.5V----------105V
Locations (0,0), (1,0), and (1,0) are all still below the strike
voltage.
For turning off location (1,1):
7.5V 15V
X0 X1
| |
| |
97.5V Y0 --------90V-----------82.5V
| |
| |
90.0V Y1 --------82.5V----------75V
Locations (0,0), (1,0), and (1,1) are still above the maintain
voltage.
Analysis is easier if you center the voltages around zero, as
in my later posting. My original numbers are centered but with
a fixed DC offset.
I wrote:
Will neon bulbs have reduced lifetime if you run them
on DC?
Tom wrote:
As far as I can tell from reading literature,
basically the metal
electrodes develop non-conducting surfaces (eg. oxidation) from
impurities in and outgassing from the glass and metal.
Chicago Miniature Lamp says that DC operating life is 60% of AC.
However, the lifetime specs given for "circuit element" lamps (as
opposed to "indicator") are for DC.
Eric