Peter Tiang wrote:

> There are actual light bulbs that simulates candle light,
> made of two (just) touching filament shaped like a candle flame
> (teardrop)

  The description of a "filament" shaped like a teardrop sounds a bit
odd to me, and bimetallic switch flashers are generally a bit slow.

  You're not confusing this with a standard "flicker flame" neon are
you?  These have been used for most of my lifetime(!) and contain a pair
of parallel "teardrop"-shaped electrodes excited by the AC via a
resistor in the base.  I presume the facing surfaces of the electrodes
are covered by an insulating coating.

  Since the neon glow discharge area is directly proportional to the
current flowing, in these lamps the current is such as to light only
half the area of the electrodes.  With the electrodes flat and parallel,
and I suspect dependent on heating effects and the electrode coating,
the glow is unstable and rapidly moves to occupy different areas on the
electrodes, causing the "flicker" effect.

  If due to damage or manufacturing error the electrodes become other
than parallel, the "flicker" effect is compromised or lost.

  Now you've reminded me.  They used to be sold in the radio parts shops
and I've never owned one, always wanted to.  An associated device was a
glow lamp with flower-shaped electrodes in which the leaves glowed green
and the flower, orange or red.
--
  Cheers,
        Paul B.