Flashtube polarity

When I played with these things some years ago, making disco strobe lights, and car timing strobe lights, I don't recall there being any polarity issues. Just a tube with two internal electrodes, an external striking electrode, and some xenon gas, as far as I'm aware.

There is a huge amount of useful material available on the net, including a large site from Sam Goldwasser, who regularly posts on here. Just Google for " Xenon flash tubes "

Arfa

I can't see any differences between the electrodes, can you?

• Any red markings or "+" markings indicate the anode.

• With no markings but electrodes of unequal size, the larger one is the cathode.

• If both ends look identical but the trigger electrode is closer to one electrode, or more coupled to one electrode, then that electrode is the cathode.

• If the tube looks symmetric except for having a getter at only one end, it is probably preferable to make the getter end the cathode, especially if any getter material exists on the electrode itself. Any vaporized getter metal forms positive ions easily, and will be attracted to the cathode. Metal vapor released around the anode is more likely to condense all over the tube and discolor it.

• If both ends of the flashtube look alike except for one electrode being shinier and with rounded edges, then the shiny electrode with rounded edges is the anode, and the steel-gray (tungsten) sharply cylindrical one is the cathode.

--- sam | Sci.Electronics.Repair FAQ:

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Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

With some, it makes a big difference. See my other post, or the Strobe FAQ at the sites below.

--- sam | Sci.Electronics.Repair FAQ:

Repair | Main Table of Contents:

+Lasers | Sam's Laser FAQ: | Mirror Sites:

Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

Dave