Arc tubes Flash
< Mazda 24V 36W, with very odd base, believed to be for morse
signalling lamp. Bulb 1¾ dia.
> Osram 12V 350W, military, probably for small searchlight or signal
lamp. bulb 2¾" dia.
< Philips 340 lamp, 2" dia. x 4" long
Info from Ron Pond : The Philips type 340 is a current regulator tube that was used in
one of their early battery chargers. ( I think there may even have been two of these in
the one charger.)
They were designed to operate from between 3- 10 Volts at a current of 5.9 Amps, and had
an Edison Screw type base designated type as a G2 base. Incidentally, the filament was
made of pure iron immersed in an atmosphere of hydrogen gas. These tubes understandably
got quite hot in operation and adequate ventilation was essential.
>Siemens 80V 1500W signalling lamp, 3" dia. x 8" long.
See what happens when you put this bulb on a Tesla coil!
< Early top-sealed coloured lamp. Info from Ian Shorrocks :
You will note that the colouring on the outside of the bulb is quite thick and would
attenuate the light quite considerably. In fact, I think you find will that your lamp is
rated at (I'm trying to remember here, so I may not get this quite right) a couple of
hundred watts or so from a 200 volt supply. Looking around the Science Museum in the
domestic appliances gallery will reveal four more of these 'lamps' mounted in front of a
polished reflector in an electric heater. These 'lamps' are in fact the electric heating
elements for a very early electric room heater. The lamps were clearly intended to emit a
comforting orange glow as well as heat.
> Philips 240V 100W projector lamp - note bulge in side, presumably
due to insufficient air cooling.
Below - small early Mazda top-sealed 12V automotive lamp
< Early Siemens top-sealed lamp, non-coiled tantalum filament.
> Cosmos 110V 200W early top-sealed lamp
< Royal Ediswan 'Pointolite' lamp. Marked 100 c.p. (candlepower), 100-240V.
Thanks to James Hooker for the following info :
They can be thought of as an incandescent arc lamp, and are used for projection work.
Yours looks like it was made at the Ponders End, London factory around 1950, but we
carried on making them afterwards at Leicester up to around 1970. This is how they work:
First you apply about 7V through the filament which heats up. You will notice that there
is a grey ceramic tube, called the ioniser, slipped over part of the filament tail. This
is made of thorium oxide and is a great electron emitter and the filament heats this up.
Then 100-240V is applied via a resistor across the filament and the tungsten bead, and an
arc forms. The arc soon moves over to the ceramic rod as this becomes conducting when it
gets hot, and takes the load away from the fine filament wire which would otherwise melt.
The heat of the DC arc makes the tunsgten bead glow white hot, and forms a highly
efficient point source of light, almost no light is produced by the nitrogen/argon
discharge. I can't tell from your photo but yours may be of the type which has the bead
mounted on a bimetal strip, this makes sure the bead moves away from the coil and next to
the ioniser to prevent the filament getting too hot from the arc.
Here is some data on these lamps : Seimens-Ediswan
> Experimental lamp with side tube, presumably to allow gas filling
Info from James Hooker : This is probably a Pirani Gauge, used for measuring vacuum
quality. The side tube is sealed onto a vacuum system, pumped down, and a low current
applied to the filament to raise it to a couple of hundred degrees. Depending on how much
gas is left in the system, the filament temperature will vary due to thermal convection
losses in the gas. by measuring the filament resistance, you can calibrate a meter in
units of vacuum pressure, making a very effective vacuum gauge.
'Tricity Sunray Radiator' heat lamp, 10" long
Siemens 1000W 230V linear lamp, marked 'Property of H.M.Government' 12"
<Unknown flash tube, Mullard LSD3
> Philips Photoflux PF100E magnesium wire filled flashbulb.
Below: small (B9A base) EG&G FX102
Hewlett-Packard flash x-ray tube. X-Rays emerge through a
thin metal disk in the base (left).
< Mazda 250W mercury-vapour arc tube
> Unknown arc tube (left) and Manufacturers Supply Co. HF3 Hydrogen
Thanks to James Hooker for the following info on the left-hand tube :-
this is a deuterium lamp, similar to the hydrogen lamp next to it but
is contains deuterium gas instead. We still make these today, they
get used in infrared spectrometers.
Violet Arc lamp (marked D809 Germany), from a spectrometer. Probably a deuterium lamp
(about 3 inches long). The tube was sealed into a metal tube and clamped to a heatsink.
One reason for the sealing is probably to reduce ozone, which can be smelt strongly after
the tube is run for just a few seconds.
> a pair of 100 watt short-path arc lamps, used in UV recorders (chart
recorders which used moving-mirror galvanometers to record on light sensitive paper). The
right-hand one has a third starting electrode to initiate the arc.
A couple of hollow-cathode lamps.
These are used to produce precise wavelengths for spectroscopic applications. These
produce narrow emission from various metals. They have a cylindrical cathode, made from
the element of interest. The discharge ionizes rare gas (typically neon) atoms, which are
accelerated into the cathode and sputter metal atoms into gas. Collisions with gas atoms
or electrons excite the metal atoms to higher energy levels, which decay to lower levels
by emitting light.