VERY STRANGE PYGMY

[AngryHorse]

Humour me for a minute here, but I’ve just fired up a 15watt Pygmy, and it’s doing something electrically impossible??
It’s flickering, like something with a bad connection, but it’s certainly not that, I first thought it was the filament ‘wiggling’, like when you bump a tungsten lamp with a thin filament........., but it’s not that either

It’s something I’ve never EVER seen before, and should be scientifically and electrically impossible??
I’ve looked closely at the filament under a magnifying glass, and there’s no break or twist in it, but the flickering is being caused by a 2mm section of filament going out, then coming back on!!!!

Now I can understand this on a row of LED diodes, but not on something resistant heated by a flow of electricity!
I wish I could show you all this, this tiny section is not dimming it’s completely going out, then coming back on!, that can’t be????

You’re thoughts?

[Oliver]

Probably shorting out somewhere which causes it to heat and expand which makes it flash?

[Cobster]

I use 60W golfball lamps in my desk lamp at work to help keep my tea warm. They have a similar flicker but being pearl you can't see the filament. Perhaps it is the same issue.

[AngryHorse]

James has said to bring it to this year’s meet, and he will bring a microscope to look deeper into it

[AngryHorse]

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[BC5-80]

Perhaps a small segment is alternately shorting and unshorting on the support wire, with thermal expansion and contraction causing it to switch between the two states? Does it stop if you change the orientation of the lamp to let gravity move the filament to a different position?