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The Project
Most lighted viewers for Realist format
slides use what we used to call 'torch bulbs' these have a small
Edison screw fitting and burn with Kelvin rating somewhat less
than normal daylight. In more recent times, halogen lamps
have become available, with or without a frosted coating.
These give a brighter and whiter light than there predecessors but
are relatively expensive and not particularly economic with the
viewer's batteries.
In the search for a white LED light source
for my Kodak viewer, which I believed would provide a light nearer
to daylight and with lower power consumption, I came across a
direct replacement for the aforementioned lamps and purchased one
for test purposes.
Figure 1.
is a shot of my Kodak viewer. I also own other lighted
viewers which have the same lamp fitting.
Figure 2. shows an original lamp on the left,
followed by a halogen lamp with the LED to the right. The
LED lamp is in fact a cluster of three LED's
Figure 3.
shows the LED lamp fitted inside my Kodak viewer. Unlike the
other two light sources mentioned, LED's have a polarity and it is
important to ensure that the batteries are installed such that the
positive stud on the battery connects with the centre contact of
the LED. This may be through the lamp on/off button,
depending on the viewer involved.
Figure 4.
is a picture of the lamp reflector, removed from the viewer.
This can be painted with a tinted emulsion if you feel that the
LED is to white for your taste. I have in fact used white
self-adhesive labels to improve the reflectivity of a very much
faded reflector.
Below are the details for the LED that I am
using.
Forever Led Torch Bulb: 9mm
Screw Base
Voltage: DC 1.5V-9V, It can fit almost any
Torch
- Color: 3 Super White 5mm LEDs
- 60ma only Power consumption.
- Size 26mm (total 13mm from base to
top) 11mm Max Width
- Batteries Last up to 6 times longer
- Power squeezer circuit to get the last
drop of power from your batteries.
- Luminosity:
54000mcd
- Base: Scew Type
The
LED is available from Ultraleds who's website can be seen at:
www.ultraleds.co.uk
Barry Aldous - January
2005
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