| LAMPS
FILAMENTS:
Filaments are constructed of Tungsten and Tungsten / Rhenium.
When amperage is equal, temperature and brightness are greater when
a lamp filament is wound with a tighter pitch. If the pitch is the
same, the filament with the thinner wire is brighter. If you magnify
a filament it would look like fish scales.
Filaments look like miniature coil springs, the lower the lamp voltage
the shorter the coil. Therefore, a 2 cell lamp will show a much
smaller tighter spot than a 6 cell lamp because the 6 cell filament
is longer than the 2 cell.
TYPES
VACUUM: The absence of gas or air. Why do vacuum
lamps turn black?
As the filament burns, it deposits particles or scales of tungsten
on the inside of the lamp. The longer the lamp burns, the darker
the glass becomes until the tungsten filament gets so thin it breaks
and burns out.
GAS: The gases used most in today’s flashlight
lamps are:
Argon
Krypton
Halogen
Xenon
Most early flashlight lamps were either Vacuum or Argon
gas filled.
Argon: Constitutes 1% of the Earth’s atmosphere.
Low cost, also used in fluorescent tubes. The insertion of gas into
a lamp allows it to burn hotter thereby burning up the tungsten
particles and allowing the lamp to burn cleaner and longer.
QUESTION: Why then don’t we gas fill all
lamps? Answer is that low current filaments, ( less then .25 amperes
), do not respond well to gas filling. Many low current lamps are
vacuum because the efficiency or light output per watt is higher.
Krypton: There is a reason why Krypton lamps have
become so popular with flashlight manufacturers. Krypton lamps have
a higher color temperature, ( whiteness ), than vacuum or Argon
lamps. The human eye is not equally sensitive to all wavelengths
of energy, but is most responsive to wavelengths of color temperature
where Krypton lamps fall. The eye is more responsive to blue white
light and thus objects illuminated with Krypton lamps are easier
to see. Also, Krypton is heavier than Argon and conducts less heat
away from the filament resulting in higher efficiency.
Halogen: Halogen lamps are ideal when small, high-powered
light sources are needed in a low- voltage range. Halogens are noted
for their reliability under extremely rugged conditions as well
as their high shock-resistance and long life. Although Halogens
are more expensive than Krypton’s the high light efficiency,
constant light flux over the life of the lamp and brilliant white
light resulting from high color temperature makes them worth the
additional expense.
Xenon: Xenon gas is on a par with Halogen gas but
is the rarest of the inert gases and the most expensive. Because
it has a higher molecular weight than Krypton gas, Xenon lamps burn
brighter and last longer.
LAMP BASES
The most commonly used bases for flashlights are PR base
and the Bi-Pin. PR means PRe-focused. Conventional PR lamps were
designed more than 60 years ago and have changed very little in
that time. Today most PR lamps are made either by hand or by semi-automated
machines. Because PR’s are partially hand made, filament positions
are not as precise.
GLASS ( BOROSILICATE )
Several kinds of glass are used in today’s flashlight lamps.
Soft Glass, ( low temperature ): is used in most
flashlight lamps today, i.e. Vacuum and Argon
Hard Glass, ( high temperature ): is used in low
voltage high temperature lamps like Krypton, Halogen and standard
Xenon.
Quartz Glass: is used in extremely high temperature
lamps such as Xenon Arc lamps, ( not used in flashlights ).
A common fallacy is that you should not touch high temperature flashlight
lamps with your fingers or the oil on your finger will cause the
lamp to explode. This will only occur if the glass is Quartz. Touching
a Halogen or Xenon flashlight lamp will on occasion produce a little
smoke as the oil burns off and nothing more.
LENSED LAMPS: The addition of a lens to a lamp
will cause additional light gathering with subsequent increase in
intensity.
DEFINITIONS
MSCP - Means Spherical Candle Power: The value
of a total visible light emitted in all directions from a lamp,
( no reflector ). A source of one candlepower delivers one lumen
per square foot, at a distance of one foot from the source.
PBCP - Peak Beam Candle Power: The candlepower
of a lamp with a reflector as measured at the brightest or hottest
spot at a specified distance.
LUMEN: Luminous flux radiated by a light source
of one candela, ( candlepower ), in a solid angle of one steradian,
( i.e., one candela equals 4-pi lumens ). The total light emitting
from a light source, no distance required.
FOOT-CANDLE: The illumination produced by one lumen
falling on a surface one square foot in area.
WATTS = VOLTS x AMPS, ( 6 volt 1 amp. Lamp= 6 watts ).
REFLECTORS
Reflectors are a simple and important tool to increase light intensity.
As a general rule the larger the reflector the larger the light
output.
Light beams radiate from the lamp filament to the reflector and
re-radiated out. The light radiating from the inside of the reflector
closest to the lamp is directed out and seen as peripheral light,
( flood ). The light radiating from the outer edge of the reflector
is collimated to a spot.
PARABOLA: A curve formed by the intersection of
cone with a plane parallel to its side, ( the shape of the inside
curve of the reflector ).
PAR=PARABOLIC, ( COLLIMATING ).
Reflectors are designed for either a spot or a flood. Today’s
technology has not produced a reflector that can function well for
both capacities. Most flashlight reflectors are designed for a spot,
when the lamp is moved from that designed location it produces dark
rings.
REFLECTOR SURFACE: The reflectors surface can be
smooth, stippled or texture coated. A smooth surface gives the maximum
spot and distant light. Stippled or textured coating will allow
for a smoother more even light pattern at shorter distances but
will cut down dramatically on the distant light.
RECHARGEABLE BATTERIES
CARE AND FEEDING OF RECHARGEABLE BATTERIES
Who invented the first dry cell battery?
I don’t have a clue but the dry cell itself was discovered
around 100 BC. The first battery was invented in 1868.
NI-CAD = NICKEL CADMIUM: A rechargeable battery
consisting of a series of cells comprised of positive and negative
electrodes, a separator, electrolyte, metal case and cover with
a reseal able vent. The cells use Nickel Hydroxide as the positive
electrode and Cadmium Hydroxide for the Saft Battery Corp.
LIFE, The average life of a Ni-Cad battery is 300
– 1,000 charge – discharge cycles. The total cycles
depends on the size of the batteries, charge and discharge rate
and general care of the battery.
You will know when to replace the battery when the brightness is
substantially reduced or will no longer hold a charge.
A Ni-Cad battery will drain at a rate of, ( 1 ), one per cent per
day with no load or use.
MEMORY: When a battery is used for short duration’s
over and over again, ( i.e. 5-10 minutes per on time ), and then
placed on charge after each use, the battery will then create a
memory effect causing the battery to function for 5 – 10 minutes
before dying.
PREVENTING MEMORY EFFECT: To prevent memory effect
it is necessary to completely discharge the battery and fully charge
it again every 4 – 8 weeks depending on use. To erase a memory
in the battery you must charge and discharge the battery a number
of times in succession until the on Time of the battery is back
to normal. Each time you go through the cycle the battery will hold
a charge a little longer.
COST of NI-CAD vs ALKALINE: The cost of a replacement
Ni-Cad battery is $45.79. The best price for an Alkaline is $.50.
Assuming 1,000 charge cycles of life the Ni-Cad at 1.5 hours per
charge = 1,500 hours of life. Fifteen hundred, ( 1,500 ), hours
of life is 107 sets of 3 alkaline batteries, ( 321 ), at $.50 =
$160.50. This represents a 351% savings.
BATTERY LEAKS: Ni-Cad’s can leak. There is
a vent / seal in each battery, any time during a charge cycle a
battery may vent or leak. When this happens, the battery vents a
combination of Oxygen and Hydrogen gas, which is very flammable.
If a flashlight is not equipped with a vent or hydrogen eater pill
the gas may stay inside the flashlight. A static electricity charge
can cause the gas to explode. The Mag-Lite is Equipped with such
a vent and is located by one of the silver charging rings.
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Quality and dependability are the hallmarks of our flashlights.
We insist upon the same quality and dependability for every lamp
and accessory that works with them. 
•
Quality and dependability are the hallmarks of our flashlights.
We insist upon the same quality and dependability for every lamp
and accessory that works with them. 
•
Halogen Lamp for Maglite® Rechargeable Flashlight System™