Originally Posted by ccrider2
......Once that occurs, the pressure inside the fixtures changes to match the pressure on the outside to equalize again..... The article doesn't address what actually changes the internal pressure.
It does a fine job, but he did fail to mention one critical point. The internal pressure skyrockets within the plasma fixture (and halogen/UHP lamps) during operation. Plasma screens and UHP bulbs are manufactured at sea level and gas charged to be within perfect operating specs at sea level.
Thin walled high PSI gas charged glass capsules do flex ever so slightly during operation. They are not totally rigid, glass will give a little on an extemely small scale. The higher the altitude, the more the glass will flex outward...and we're talking tolerances measured within millionths of an inch here. There is no pressure regulation system to compensate for the issue. Such a design for a UHP bulb would require a ballast containing pure mercury vapor interfaced through a regulator crossed-linked back into the glass lamp capsule. From a cost and engineering perspective......that would be one $$$ and complex design. It's just not feasible for the consumer market.
I understand...The deeper a sub goes, the higher the internal pressure must be increased, or the sub's shell will implode...makes sense. I assume that's done via releasing compressed air inside the sub.
To minimize hull warpage, let alone an implosion. Right, you get it. No pressure regulation at all for plasma tv tubes or lamps however.
Why do ears pop when you change altitude in an aircraft? Could it be the the plane's atmospheric controls are regulating the internal pressure to prevent the craft's shell from being breached?...I bet so.
Your ears pop in an aircraft because the plane's atmospheric controls allow the cabin pressure to drop to a certain point. It's just enough for us to feel comfortable and most importantly, remain in an alert consciousness. The pressure regulation is to maintain comfortable breathing atmosphere and to minimize stress on the fuselage. Fuselage breaches have occurred in the past due to metal fatigue stress cracks, I don't recall any breaches due to high cabin pressure alone with healthy aircraft.
So there are tiny regulators on the plasma cells and SXRD bulbs that control the internal pressure?
I see none on my bulb....Where are these little buggers?
As mentioned earlier, nada.
This is an interesting discussion, because it peaks my curiosity of how things work. But I totally, still don't see it, and I guess.....a bit OT to carry it on here. Perhaps we need a physics forum to address these concerns.
Well hopefully you see it now. I agree it is OT to discuss it here, but what the heck.
Read my response to "Torqdog" for added info.