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Black Nixie Tube
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Black Nixie Tube

by sprite on Sun Oct 04, 2015 4:26 pm

My Nixie tube is black/burned on the back. Is this normal or do I need a replacement? Don't want to solder it to the board until I know if I need to replace it or not.
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sprite
 
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Re: Black Nixie Tube

by cconradd on Sun Oct 04, 2015 5:57 pm

Normal.

I also wondered this at first but after some googling it appears they all look this way.

Image

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Re: Black Nixie Tube

by sprite on Sun Oct 04, 2015 6:42 pm

Thanks

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Re: Black Nixie Tube

by jarchie on Sun Oct 04, 2015 7:02 pm

The black spot is actually an important part of the tube design. Vacuum tubes require an almost perfect vacuum, but removing all gas is nearly impossible. Even worse, the tube walls and other components release absorbed gas long after manufacture. The black spot, called a "getter," is added during manufacture. The getter is composed of reactive material that binds gas. So the black spot is effectively a chemical vacuum pump and is active for the life of the tube.

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Please be positive and constructive with your questions and comments.