Light sources Halogen low voltage incandescent lamps (12 V) Electrodeless fluorescent lamps
are important elements of modern lighting
In traditional fluorescent lamps the electrical
Traditional incandescent lamps
architecture. Their small, solid filament in
discharge required to create light takes place
conjunction with respective reflectors produce
between two electrodes the wear and tear of
incandescent lamps in lighting systems. They are
narrow beams. There are many types available.
which determines the life time of the lamp. The
economical to install since they require just a
They include those with cold light reflector to
way of operation of the electrodeless fluorescent is
lampholder and two terminals. Their operating
reduce the temperature load on the illuminated
totally different. Its discharge has neither
position is not critical. They are almost indepen-
object. Lifetime of these lamps - depending on the
beginning nor end. The closed circle enables a
dent on ambient temperature and can easily be
discharge process that needs no electrodes. The
dimmed by phase control or phase reverse control.
required energy is induced from outside by
Luminaires for incandescent lamps may as a
Halogen low voltage incandescent lamps must be
magnetic fields. A very decisive fact for long
standard be operated on 115 V or 230 V by simply
powered through either conventional or electronic
changing the lamps. The average lifetime is 1000
transformers. There is no problem in dimming
The electrodeless fluorescent lamp features
Incandescent lamps for navigation lights are a
special case. They were developed precisely for
- 12000 lumen luminous flux in the 150 watt
application within an optical system and thus
differ in many aspects from standard lamps:
- 8000 lumen luminous flux in the 100 watt
- They have a special lampbase to make sure only
these especially approved lamps are used in
- Extremely long life time of 60,000 hours and this
navigation and signalling lights. Moreover the
Halogen high voltage incandescent lamps
does not mean the lamp will be defective by
particular base ensures the lighting filament
are still rather new light sources. They are
then but just that the luminous flux will have
available as standard with bases E14 and E27.
They don’t need a transformer and may replace
- Their maximum light efficiency / minimum
traditional incandescent lamps without any
aqua signal has succeeded in even improving the
power consumption ratio is set to its best.
modifications. Their lifetime is about 2000 hours.
outstanding properties of the electrodeless
- Their lighting filament is suspended in a very
fluorescent lamp. An optional device extends the
special way to prevent screening the filament in
admissable temperature range to -50° until +50° C
without noteworthy loss of luminous flux.
- Their production process is particularly
sophisticated for smallest tolerances with thefilament and its suspension.
- They are approved by the responsible authorities
of almost all important countries in the world.
Their advantage is their excellent economy. Theirlight efficiency per watt of invested power (lumenper watt) is very high. The elongated shape results
in a low luminous density on their surface and
There is no other light source that offers to the
thus in little glare. Lifetime is about 8000 hours if
operated with conventional ballast respectively
facilities. Neon lamps are produced by hand to
about 12,000 with electronic ballast. Fluorescent
customers requirements and are available in each
lamps may be dimmed down to 1 % of their rated
Traditional incandescent lamps lose part of their
luminous flux without any problems if operated by
Neon lamps are cold cathode lamps which means
light intensity in the course of time since tungsten
their lifetime is not limited by wear and tear of the
evaporates from the filament and condenses on
filament. This results in a life expectancy of 60,000
the inside surface of the bulb forming a dark layer.
hours. They need a high operating voltage which
In modern halogen lamps they prevent this effect
depends on the lamp’s diameter and gas filling.
by adding halogenes to the filling gas. Within the
With a diameter of 10 mm it is about 500 V per
so-called halogen cycle the halogenes combine
meter and with a diameter of 18 mm about 280 V
with the evaporated tungsten. This gaseous
per meter with discharge in blue. It is by about 50
combination drifting with the heat flow towards
Tubular compact fluorescent lamps (TC-lamps)
the hot filament the tungsten will leave the
Neon lamps with blue discharge may be dimmed
combination and re-join the filament. The released
dimensions of fluorescent lamps to almost those
down from 100 to 5 % by means of the excellently
halogenes are again available for the cycle.
of traditional incandescent lamps by bending the
adapted electronic ballasts from aqua signal.
tube and splitting it into a bunch. Compact
fluorescent lamps are available in different shapes
- equally bright light throughout life time
- nice, brilliant light for fresh colours and
- increased light output with same power con-
- those with E14 or E27 base and internal
sumption improves the economy by about 25 %
electronic ballast to directly replace traditional
LED (light emitting diode)
compared with traditional incandescent lamps
An LED is an electronic semi-conductor producing
- those with 2 connection pins for operation with
light under the influence of electricity. This does
conventional ballast with the starter being
not happen by heating a filament or by gas
discharge but is a result of effects inside the semi-
- and those with 4 connection pins for operation
conductor. An LED supplies light only within a
with electronic ballast. Controllable electronic
narrow window of the spectrum i.e. of a precisely
ballasts enable dimming down to 10 % of the
126aqua signal – Light for Ships / Licht für Schiffe
Technical modifications reserved without prior notice / Technische Änderungen vorbehalten
Two processes have been developed to produce
Connection diagrams: Fluorescent and
white shining LEDs. One combines several LEDs of
compact fluorescent lamps
different colours in a common housing thusmixing the colour fractions into white. The otherone provides an inside layer in a blue LEDtransforming part of the blue light into other
High pressure sodium vapour lamps with instant
colours thus providing all fractions of the
spectrum that again add up to white light.
have bases at both ends and need a special
It is the long lifetime of more than 100,000 hours,
ignitor. In hot condition the lamp requires about
little heat production, and mechanical robustness
10 seconds to ignite which is of particular
compared with conventional incandescent lamps
that disclosed new application fields to the LED. Metal vapour lamps High pressure mercury vapour lamps
are similar to high pressure mercury vapour lamps
These lamps don’t need an ignitor but a ballast.
concerning design and operation. Light output and
There are types with E27 and with E40 base.
colour response have been improved by adding
The high pressure mercury vapour lamps contain
some halogen combinations. Depending on the
a quartz burner as discharge tube. This tube is
type they may operate with or without ignitor.
positioned inside a glass bulb on the inner sur-
There is a special version with one base at each
face of which there is a fluorescent layer.
end of the bulb enabling instant re-igniting in hot
Having been switched on the burner slowly gets
condition by means of a high voltage puls.
hot thus making more and more mercuryevaporate. The more mercury evaporated thebrighter the light output. All mercury evaporated
means the lamp features its rated luminous flux.
Metal vapour halogen lamps and high pressure
The average lifetime of this lamp is about 6000
sodium vapour lamps require a voltage of between
800 and 5000 V to start working. There are two
Its disadvantage is that it reacts to shortest
different igniting device systems. One is based on
interruptions of power supply and to severe
additional voltage load and the other one on
voltage fluctuations by extinguishing and then
pulsation technique. aqua signal has decided in
needing several minutes to re-ignite.
favour of the modern extra voltage load system. Itsbig advantage is that the ignitor produces theignition voltage without loading it on the ballast.
D) Inductive wiring in series l.p.f.
This is of particular importance towards the end ofthe lamp’s lifetime when the ignitor tries againand again to re-start the exhausted lamp. Moreover the extra voltage load technique offers
Low pressure sodium vapour lamps
reproducible ignition properties independent on
have the best efficiency of all conventional light
sources i.e. the highest light gain but a restrictedcolour response. They are suitable for all
aqua signal’s ignitors for high pressure discharge
applications where recognition of colours is of no
lamps have currently been improved to adapt
E) Capacitive wiring in series l.p.f.
importance. Monochromatic yellow light enables
them to the extremely rough operating conditions
contrasty seeing also in smoke and fog.
our floodlights have to meet with. They may be
You need a ballast. The average lifetime is about
called unique since they not only ignite the lamps
tenderly but also supervise ignition process andoperation and recognize lamp failures due toageing in which case they carefully switch thelamp off. High pressure sodium vapour lamps offer much light output because of their high efficiency despite of their small dimensions. They are little sensitive to vibration and have proved as outdoor floodlights on board of ships. You need a ballast and an ignitor. The average lifetime is about 6000 hours.
Technical modifications reserved without prior notice / Technische Änderungen vorbehalten
aqua signal – Light for Ships / Licht für Schiffe127
Acta neurol. belg. , 2007, 107 , 5-10 Original article MEG evaluation of Parkinson’s diseased patients after external magnetic stimulation P. ANNINOS1, A. ADAMOPOULOS1, A. KOTINI1, N. TSAGAS2, D. TAMIOLAKIS3 and P. PRASSOPOULOS41Lab of Medical Physics, Medical School, Democritus University of Thrace, Alex/polis, Greece ; 2Lab of Nuclear Technology, Dept of ElectricalEngineering and