Microcrystal Carborundum Silicon Carbide Crystal Radio Detector Diode Brass Cup

Description

Microcrystal
Silicon Carbide Crystal Radio Diode Cast in Brass Cup
Amazing Silicon Carbide (Rainbow Carborundum) crystal
Experimental Crystal For the Experienced Crystal Radio Enthusiast
Silicon Carbide
does require a heavier pressure from the cat whisker contact, and i
t is not sensitive to vibration and so was often used in shipboard wireless stations where the ship was rocked and tossed by waves, and military stations where vibration from gunfire could be expected. Another advantage was that it was tolerant of high currents, and could not be "burned out" by atmospheric electricity from the antenna.
Silicon carbide is a semiconductor that may need some biasing
(see picture)
to make the detector more sensitive with a forward
bias
voltage of several volts that is usually applied using a battery and a potentiometer.
Silicon Carbide
C
rystal Detector ( Actual crystal will vary in shape and size from picture)
Crystal mounted and Cast in a 13mm" Diameter brass cup
Casting alloy is made from Lead,Tin and Bismuth-Cadmium Free
FACTS ABOUT OLD SCHOOL CRYSTAL DIODES
Not every contact position on the crystal will perform, so fiddling with the ‘cat's whisker’ to find a sweet spot does take patience and some acquired skill.
Cat Whisker:
The "cat whisker", a springy piece of thin metal wire, formed the metal side of the junction. Phosphor bronze wire of about 30 gauge was commonly used because it had the right amount of springiness.
Cat whisker detector:
It consisted of a pea-size piece of crystalline mineral in a metal holder, with its surface touched by a fine metal wire or needle (the "cat whisker"). The contact between the tip of the wire and the surface of the crystal formed a crude unstable point-contact metal–semiconductor junction, forming a diode. The wire whisker is the anode, and the crystal is the cathode; current can flow from the wire into the crystal but not in the other direction.
Having a lot of patience and a steady hand are needed when you listen with a piece of the rock. But this can also be very rewarding when you can hear the first station using a cats whisker detector.