From the beginning of history, people have
always needed portable light sources. Torches, candles, oil lamps and kerosene
lamps were designed to be carried around, but they could be dangerous because flame
was the source of light. Inventions of incandescent electric light bulbs and of
dry batteries at the end of the 19th century enabled a solution for this
problem.
The first dry cell battery was invented in
1896. It was an improved variant of the previous version in the way that its
electrolyte was a paste instead of liquid. Because of that, it could work in
any position and it would not break or spill that easily. It was a perfect
power source for a portable light source.
In 1899, English inventor David Misell
invented the first flashlight. It had three D batteries placed in a tube that
acted as a handle of the device. Batteries powered a small incandescent
electric light bulb and a simple contact switch turned light on and off. They
were called “flash” lights because they could not throw light for too long and
you had to turn them off to “rest” from time to time. Early flashlights ran on
zinc-carbon batteries that could not give constant current for long periods of
time.
The first flashlights did not sell too well
because of the behaviour of the batteries and because carbon-filament electric
bulbs were inefficient. Replacing of carbon filament with tungsten and improving
of batteries made flashlights a more useful device, which increased its
popularity and it started to replace lamps with flammable fuel. By 1922, there
were several different designs of flashlights. There was classic cylindrical
variant, a lantern-shaped version that could be left to stand, a reflector type
for lighting a greater area and a small pocket variant. Different varieties and
usefulness were reasons of the high demand, which resulted in 10 million
flashlight users by the same time.
Modern flashlights generally have similar
parts and work basically the same. They most commonly use incandescent light
bulbs or LEDS. Incandescent light bulbs have a tungsten filament in a glass
bulb in the atmosphere of a vacuum or of gas xenon, argon or krypton; noble
gases that reduce evaporation of filament and with that make lamp last longer.
Light Emitting Diodes (LEDs) are electronic
elements, semiconductors that emit light. Types that are used in flashlights
are of white high-power kind. They are much more efficient than incandescent
light bulbs and last longer. As a source of energy they mostly use batteries,
but they can use accumulators or super-capacitors, they can be charged by solar
power or mechanically. They are made like key rings or pens, as headlamps on
helmets, with clips for mounting on rifles and as high power reflectors. We
have them on mobile phones and in hundreds of other variants.
The flashlight is an object that basically
started as a novelty and then turned into a necessity with thousands of possible
uses. Pretty impressive, right?
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