[time-nuts] Old Crystal.

[Mike Feher]

During WWII the Germans had crystals that glowed at resonance. Some place I
have about a dozen of them on different frequencies. These were mainly used
for calibration purposes, much like in our ARC-5 transmitters that utilized
a crystal and a magic eye tube. About 55 years ago I had an old German radio
guy tell me about crystals that glowed. I thought he was crazy. Turns out he
was right. 73 - Mike 

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

 

-----Original Message-----
From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of ed breya
Sent: Saturday, March 6, 2021 5:42 PM
To: time-nuts at lists.febo.com
Subject: Re: [time-nuts] Old Crystal.

 

Haha - interesting pictures. It looks like they really do glow, but I doubt
it's from anything the crystal element is doing - it and the mount structure
may just serve as the electrodes for a gas discharge lamp. If the envelope
is filled with some relatively "inert" gas or mixture, instead of vacuum,
then you have a discharge lamp. Using say, dry nitrogen or krypton (common
fillers, I think), you may get the bluish color at some conditions. If you
excite it with high enough AC voltage at limited current, it will strike and
run.

 

I doubt that the crystal would be mechanically damaged unless you could
somehow apply the excitation at "exactly" the resonant frequency, but I'd
think it would become no good as a normal crystal anymore, since various
things could deposit onto or depart from the surface, affecting the
resonance and Q. If the voltage is high enough that it arcs over and ruins
the connections, that's another story. The voltage will at least be limited
by the gas. If the current is allowed to get too high, then the whole thing
will be shot.

 

Ed

 

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