What technology is this night light?

[Liron]

I've had a particular night light bulb from the 70's sitting in my cupboard
and I would like to know what technology it's based on.

The bulb is very small (like a pygmy bulb or pilot bulb, maybe shorter) with
a diameter of one inch, and has a B22d socket that would fit into an AC
powered lamp (240V AC). I am in Australia where B22d screw bases and
230V-240V AC are normal.

Inside the bulb there are two posts that come up from the socket. On top of
one post is a black disk which sits near the top of the bulb and which is
centred around the axis of the bulb. On top of the other post is a black
ring which is positioned just above the disk. The ring goes almost all the
way around, but not completely all the way.

When the lamp is turned on, the posts, disk and ring all glow pink-red. The
glowing flickers, either at the line frequency or double the line frequency.
There is a haze of purple or UV around the glowing posts, disk and ring.

This bulb has a very long life. When I was a kid, it would be on for 8-10
hours a night for years and years.

Any ideas? Also, what chemicals would the bulb contain and are they safe?

Liron

 

[Don Klipstein]

I've had a particular night light bulb from the 70's sitting in my cupboard
and I would like to know what technology it's based on.

The bulb is very small (like a pygmy bulb or pilot bulb, maybe shorter) with
a diameter of one inch, and has a B22d socket that would fit into an AC
powered lamp (240V AC). I am in Australia where B22d screw bases and
230V-240V AC are normal.

Inside the bulb there are two posts that come up from the socket. On top of
one post is a black disk which sits near the top of the bulb and which is
centred around the axis of the bulb. On top of the other post is a black
ring which is positioned just above the disk. The ring goes almost all the
way around, but not completely all the way.

When the lamp is turned on, the posts, disk and ring all glow pink-red. The
glowing flickers, either at the line frequency or double the line frequency.
There is a haze of purple or UV around the glowing posts, disk and ring.

This bulb has a very long life. When I was a kid, it would be on for 8-10
hours a night for years and years.

Any ideas? Also, what chemicals would the bulb contain and are they safe?

That sounds to me like a mixture of neon and argon, with more argon than
the common 99.5% neon .5% argon mixture. It could be some other neon
mixture.

I have seen a few neon lamps with a neon-krypton mixture. The glow on
the electrodes is somewhere between orange and rose pink and there is not
much haze.

Pure neon glows a bright reddish orange.

The 99.5% neon .5% argon mixture, in lamps with a main discharge column,
has the discharge column glowing anywhere from magenta-purple to
hot-pinkish-red, depending on current density. Electrode glow (as in
neon glow lamps) in this mixture tends to be orange, less reddish than
with pure neon.
Apparently, in that particular mixture, argon produces negligible
visible glow in the cathode/negative glow and detracts from the brightest
yellow wavelength of neon (585.2 nm) less than others.

In glow lamps, mainly ones larger than the NE-2, a neon-argon mixture
often produces a violet or purple haze around the electrode glow.

- Don Klipstein ([email protected])

 

[Liron]

Thanks to everyone for all your responses. It looks like it's a neon lamp
with possibly some argon or krypton. BTW: the colour of the light is rose
pink.

Liron