Sunday, 8 July 2012

Electroluminescent Silicon Carbide Crystals in 1907

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Electroluminescent Silicon Carbide Crystals in 1907
An Early Light Emitting Diode.

A Note on Carborundum, from Electrical World Feb 9th 1907

To the Editors of Electrical World:
SIRS:- During an investigation of the unsymmetrical passage of current through a contact of carborundum and other substances a curious phenomenon was noted. On applying a potential of 10 volts between two points on a crystal of carborundum, the crystal gave out a yellowish light. Only one or two specimens could be found which gave a bright glow on such a low voltage, but with 110 volts a large number could be found to glow. In some crystals only edges gave the light and others gave instead of a yellow light green, orange or blue. In all cases tested the glow appears to come from the negative pole, a bright blue-green spark appearing at the positive pole. In a single crystal, if contact is made near the center with the negative pole, and the positive pole is put in contact at any other place, only one section of the crystal will glow and that the same section wherever the positive pole is placed.
There seems to be some connection between the above effect and the e.m.f. produced by a junction of carborundum and another conductor when heated by a direct or alternating current; but the connection may be only secondary as an obvious explanation of the e.m.f. effect is the thermoelectric one. The writer would be glad of references to any published account of an investigation of this or any allied phenomena.
New York. H.J.Round.

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Unrelated to this post, below is an example of
eclectic science esoterica 

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WARNING - Many subjects outlined within this site are extremely dangerous and are provided here for information only. Please don`t experiment with high voltages or chemicals unless you are fully conversant with safe laboratory practices. No liability will be accepted for death, injury or damage arising from experimentation using any information or materials supplied.