- Joined
- Oct 24, 2009
- Messages
- 2,738
- Points
- 63
Startup, I switched on the white one 30 seconds ahead of the left.
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
I think what you're describing is a germicidal lamp. Most fluorescent tubes are preheated like that when they start, but it's not really to heat up the mercury - it's to heat up the electrodes. It's like preheating the cathode in an argon laser. This is done so that the "thermionic emission temperature" is reached so that the voltage drop across the electrode itself is much lower. This allows the open-circuit voltage to discharge across the tube. It's like a regular fluorescent tube, but with a quarts wall and no phosphors.
Huh. Is that the normal color (red) of the MV 30w on the left, or is that the penning mixture/startup phase?
My neon purple cat...blue neon dolphin
Since a mercury bulb has lots of green and blue, but very little red, it can make people look like corpses. So many MV bulbs have a fluorescent coating on the outer bulb to convert some of the UV to red. Just after powering on, there is an initial high ratio of UV to visible light, so there is more red from the phosphors than blues and greens from the arc tube.
Even though every light emitting device in a strange shape tube is colloquially known as a neon light, these are in fact just cold-cathode fluorescent lights. Neon emits only an orange-red light. Any tube that has a coating on it is argon/mercury.
Dave - What was the intended purpose of the DoAll monolight?
Your purple Argon indicator lamp is sweet too.
Nice craftsmanship on the home made gypsum lamp.
**EDIT** I did some quick research on the DoAll. Apparently it is helium, not neon. It looks like it might have been originally used to check for flatness in "lapping" operations.
I figured it had to have some specific purpose. "Lapping" as in polishing glass?
Something that elaborate is just too complex to be a portable flashlight.