AC viewer bulbs

[fj834@xxxxxxxxxxxxxxxxxxxxx (Dr. George A. Themelis)]

John Dukes asks:

>But my question is whether there is a perceptible difference between
>the quasi point source of the halogen bulb and the more distributed
>(quasi diffuse) source of the bigger bulb. 

The quasi point source of the halogen bulb tends to cast shadows of the
filament-supporting wires.  That's why the forsted glass is a great idea
(actually transforms the quasi point to a quasi diffused source).  The size
of the source will only affect the light uniformity.  However, there are
other differences between the two bulbs, not related to the size of the
source.  The AC bulbs tend to give warmer (read: orange) light.

Using a 75V bulb at 120V is a solution for getting brighter and more white
light.  The orginal bulb in the AC viewers was rated 80V.  My 75V bulbs
will not take much abuse (turning them on cold at 120V is abuse in my book)
and I recommend turning them on at a lower voltage and then increase it, or
even running them as less than full power on a routine basis.

John, when you apply 140V to the 120V bulb, do you increase the voltage
slowly or do you just start it at 140VC?  What's your experiece on the life
of the 120V bulb running at 140V?

George Themelis


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