Mystery component - a mysterious lamp bulb

Thread Starter

q12x

Joined Sep 25, 2015
1,453
I got this lamp bulb in a box with other electronic components from a old timer who wanted to not throw them to bin but to pass along. A lot of resistors I got from him as well, if you remember. Haha.
20221005_203547.jpg
I have 2 variable power supplies:
The famous STP3005 which is a DC 0-30V and the vevor variac 0-330AC both bench supply.
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So I have good means to test this component !
My original thought is to put it directly to the DC power supply, and ramp up the voltage until I can see something is happening with the component. THen, if the component is not DC, I will use my AC variator and ramp up with it at a much higher voltage than the DC one. If I add a rectifying bridge to the AC variac, I can power up with DC voltage way over the limited 30V of the STP3005.
But before doing anything, because I sincerely dont know anything about this type of lamp, I think is best to ask first and do later.
By looking on the metal inscription, it says 120 in the middle, but no AC or DC. It assumes you have to know it already. Or that is the number of the component production. Who knows. Its the only hint I can get from it. Nothing else.
My best Guess, this is a lamp used in old photo blitz, but those big ones, not incorporated into the photo aparat. 'External blitz vintage' is what I searched for, to show you this image here. I know it because my father used a couple of them and if I remember right it was using this kind of lamp bulb, or very similar. But this is the closest idea I may have about this kind of lamp. I may very well mistaken about it.
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- My question to you, is how I can make it work? How should I proceed?
Thank you !
 

Ian0

Joined Aug 7, 2020
6,322
It needs DC supply of about 300V and a 4kV pulse on the metallised stripe on the outside of the tube to make it strike. It will continue to conduct until the capacitor is discharged.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,453
Aha, so I think I was right, it is from a blitz, right?
I also read on your link page:
UV !!! Which means Ultra Violet which means I can get blind if I expose it too much time on my eyes.
OR
There are other types that are more UV and other types that are not UV at all ? How can I differentiate.
I know the UV is a very nice to look at blue turquoise color, but extremely harmful for eyes and skin.
UV light is emmited from stick welding and I have good experience with it, because I got #2 burn from skin exposure from welding, It was on my leg, not my eyes. I got treatment for it and was cured in about 1month completely. So I know exactly what UV light exposure can do. I am very careful about it.
But if it is not UV? .... Hmmm thats my curiosity. Also lets make it work first. For precaution, I can put it in a box, and put a filter colored glass to look through it. I can use those plastic bags used in antistatic for components for filter as well. I also have welding 'black' filter glass as well.
But until then, how to power it up?
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Thread Starter

q12x

Joined Sep 25, 2015
1,453
It needs DC supply of about 300V and a 4kV pulse on the metallised stripe on the outside of the tube to make it strike. It will continue to conduct until the capacitor is discharged.
Can we make such a driver?
The european and romanian mains is 240VAC. I believe that is good enough and close enough to the 300V. It will have to wait a bit more time until is finish charging up. I have a lot of high capacity and high voltage capacitors. So that's no issue.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,453
All I know they are expensive and not that easy to get one. At least that was the case in the 90's and I remained with the memory from then.
All im interested is to power it up and check if is working or if is burned. If is burned I will throw it away. But is a shame to throw it away if is good and working. Especially having such good american friends here. Right? Haha.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,453
Remember you need DC for the lamp. 240VAC rectified is about 340VDC. So you’re closer than you think.
But on it is written ---120--- thats why I stopped conducting any kind of experiment by myself and ask first.
I am imagining that 120 marking is the working voltage? Maybe?
 

djsfantasi

Joined Apr 11, 2010
8,583
120VAC rectified is ~170VDC… you multiply the AC voltage by √2 to get the DC voltage. AC voltage ratings are RMS (Root Mean Squared). The voltage is a sine wave whose peak value is 1.414 times the rated voltage. When converting to DC, these peaks add up and you get the higher voltage in DC.
 
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Thread Starter

q12x

Joined Sep 25, 2015
1,453
Im always available to discuss this delicate circuit in private. I also can stream live what Im doing with live (poor) image but good enough and with live voice.
If its too delicate to discuss it here publicly.
 

djsfantasi

Joined Apr 11, 2010
8,583
Im always available to discuss this delicate circuit in private. I also can stream live what Im doing with live (poor) image but good enough and with live voice.
If its too delicate to discuss it here publicly.
This is a forum. We discourage private discussions, as that is anathema to the purpose of a forum.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,453
I can use my variac to slowly and gradually rise up the rectified voltage after a rectifying bridge. Just a thought.
OR
a circuit for a blitz ? I searched myself for one but I didnt get anything useful from google.
 

MaxHeadRoom

Joined Jul 18, 2013
26,003
You charge up a suitable electrolytic, then switch over to the tube to discharge the cap, this is how it was done in the camera flash lamps.
(I used to have the one that preceded it, a flash pan of magnesium powder ignited by a flint wheel.) :eek:

1664998053310.png
 

Thread Starter

q12x

Joined Sep 25, 2015
1,453
You charge up a suitable electrolytic, then switch over to the tube to discharge the cap, this is how it was done in the camera flash lamps.
(I used to have the one that preceded it, a flash pan of powder ignited by a flint wheel.)
WOW that is cool ! I believe they used gun powder with aluminium powder mixed and ignite that for the flash. Hahaha. Yaah. I know ---a bit--- of photography history. Not much.
How does such circuit looks like? I cant imagine.
I will draw a quick one myself but Im very sure I will get into the woods with it. You will have to correct it, for me.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,453
This is how I imagine the circuit should be:
Please correct it since I imagine it as I believe it should be. I didnt find any circuit online.
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