On Wednesday, 28 June 2017 22:07:13 UTC+1, John-Del wrote:

One more thing: if you look at a halogen lamp crosseyed the filament will fail from the shock of your stare.. The filaments are not supported as they are in a standard incandescent lamp so they must not be subject to shock or vibration.

Ah, that'll be why they've been so popular as car headlamps.
It's the thin mains 50w ones that don't like vibration.


NT