I dig my tube boxes and found this old tube. Not a really expensive or most wanted tube, yeah… just an old Western Electric 393A tube. It’s a Argon and Mercury Vapor filled Thyratron tube. According to the datasheet, the addition of Argon gas on the Mercury Vapor atmosphere allows the tube to start conducting at low temperature. Ok, forget those technical literature, just watch the tube in action.
I heat up the tube for a while. According to the manual, to maintain the life span, it’s recommended to heat it up first. I give around 3-4 minutes. You can see the filament is glowing inside the metal bracket on the center of the tube.
Time for action, activate the High Voltage… Voila, the sky of blue on the top of the tube. Very beautiful!!! You still can see the red filament glowing inside the blue Mercury atmosphere.
I also take another shoot. This one is my 12B4A tube. I like the color and the design of the tube (with a straight glowing bar from bottom to the top).
I will keep posting other glowing tube if I can find some more. Time to dig some of my old tube again 😉