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Hmmmm. Wonder if you could just induct through the glass with coils on each side? Seems perfect for high voltage applications?
Hmmmm. Wonder if you could just induct through the glass with coils on each side? Seems perfect for high voltage applications?
But most hollow-state devices run on either DC or pulses, so coupled inductors wouldn't work.
Earlier quoted context omitted.
As mentioned in TFA, the most important factor for successfully joining a metal and a glass is to match their thermal expansion coefficients. Most pure metals have a much greater thermal expansion than any glass, which will cause cracks. In the nineteenth century, the first successful joinings of metal with glass were done using platinum, but that is obviously too expensive for normal applications. Eventually a speci…
Ordinary incandescent bulbs must have similar sealing requirements, but they probably mostly rely on using a thin conductor that doesn't contract much when it cools. Also IIRC modern incandescent bulbs do not use a high vacuum but contain a low pressure inert gas so leakage would be slower if it occurs at all.
I was once entertaining the idea of using gallium for an electrostatically or MHD boosted Sprengel pump, but figured out sticking would make it infeasible. And now it's unobitanium too.
Earlier quoted context omitted.
I was under the impression that they were only made in eastern Europe at this point, former bloc nations. Even then, the demand must be microscopic at this point.
xray, photomultiplier and laser tubes are still SOTA. PM tubes in particular have a huge number of glass feed through for the intermediate plate voltages.
But power tubes need to pass some decent amounts of plate current through some of the pins. Even small signal tubes have considerable current going through the heater filaments; you don't want hookup wires for that which are like metallic spider silk.
I was wondering about the feasibilty of this, but I thought that useful tubes needed a harder vacuum than that. Is this really "good enough" for a triode? I figured the wire-holding/element-holding aspect of a standard tube was in the base, and the glass-to-base seal is the important part. You can have a less-hot metal holding the filament and penetrating through the base. But I haven't looked carefully. These are my…
Probably not. The classic fix is a "getter".[1]