Topical tip: Adapting a table lamp to an LED based external microscope lamp
by Les May, UK
A simple mains operated lamp for non-critical microscopy applications which combines low heat generation with ample light output can easily be constructed from an 18 LED solid state lamp having an E27 base and an adaptor converting the screw fitting to a bayonet cap. The bayonet cap of the adaptor fits into any swan neck or similar table lamp.
The lamp I used was obtained from Lidl supermarket and cost £4.50. An E27 to bayonet adaptor came from my local market and cost £2.45. At 50mm diameter and 72mm long the lamp is rated at 1 watt.
Similar white light lamps, some with 20 LEDs, are available from stores which can be located via the World Wide Web. Also available are lamps with clusters of 18 or 20 red, green and blue LEDs which would provide monochromatic lighting for use with optics having less than perfect colour correction.
Using lamps with an E27 fitting simplifies things considerably. Other fittings are available which seem to be intended as replacements for halogen lamps in ceiling lights. These may prove to be less convenient.
In use there is ample light for use with a x40 objective and a x10 eyepiece. At 100x the image is bright but still comfortable. At lower powers some attenuation is necessary. This need be no more than a piece of kitchen paper in front of the lamp. Lighting is even across the field.
Comments to Les May welcome.
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Published in the February 2010 edition of Micscape Magazine.
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