[photo-3d] Viewer illumination

["Dr. George A. Themelis" <drt-3d@xxxxxxx>]

Perhaps the simplest way to get a couple levels of illumination
with a battery operated viewer is to use different light bulbs.
For example, these bulbs will give you a good range:

No. 14, no 245, Halogen 0.5A, halogen 0.8A

Note that the different illumination levels are needed IMO
to match the ambient light, not to adjust from slide to
slide.

>Also, for those who find halogen bulbs to be too expensive and/or hard to
>get (i.e. only available by mail, not locally) there is a pretty good option
>available at Radio Shack which is the K222 screw base krypton bulb which is
>between $1 and $2 (I don't remember exactly) and is almost as bright as a
>halogen. It is rated at 2.33 volts and 600 mA.  I think I heard about these
>on a Viewmaster list, and don't recall if they have been mentioned on this
>list.  -Linda

I was VERY excited when I discovered these bulbs (before I had
a reasonably priced source for the halogen bulbs).  Unfortunately,
they proved to be very disappointing.  Their quality varies and
they tend to burn out very quickly.  I did controlled tests and
bulb after bulb failed in very short times.  I concluded that
these bulbs were designed for a pair of AA batteries in "pen"
type flashlights.  If you run them in D alkaline cells (which
is what you should use in your stereo viewer), the higher voltage 
will kill them quickly (note they are rated 2.33 volts to start, 
instead of 2.5 like the rest).

I figured that if the halogen bulb lasts 10 times longer
(which is true), there is no money savings using the K222
krypton bulbs.  Also, having a bulb burn in the middle of a 
viewing session with no replacement on hand is no fun.  So,
I've been using the halogen bulbs ever since.

George Themelis

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Old school buds here:
http://click.egroups.com/1/4057/8/_/160438/_/959306570/
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