The Invention and Inner Workings of the Fluorescent Lamp

I have just finished my new book “Eureka!”. It is all about those

emotional moments in history when a new product or course of action was first discovered

(if you want a copy please email me at [email protected]) . One of the inventions that did not make

it into the book was the fluorescent lamp (or tube). That is not to say it isn’t

a fascinating story – it certainly is. The trouble is that there is not one big

“eureka” moment. It could be said that the fluorescent lamp was never

really invented at all but that it evolved over time.

The creation of the fluorescent lamp was a truly joint effort spanning a

century: Here are the milestones:

1675: Jean Picard, a French astronomer, noted that mercury in a barometer

tube would glow when shaken. He recorded this observation but did not understand

it

1846: Julius Plücker, German mathematician and physicist, theorized and

experimented with coloured light produced by passing electricity by various

gasses. He worked with glassblower Heinrich Geissler who invented what was to

become known as the Geissler tube in which the experiments were conducted.

1850’s: Heinrich Geissler continued to develop light emitting tubes

1857: Frenchman Alexandre Edmond Becquerel experimented with electric

release tubes coated on the inside with various luminescent materials

1868: Becquerel published his landmark treatise La Lumiere, ses causes et ses effets

1893 Nikola Tesla, originally from Serbia, developed the fluorescent light

using high frequency lighting ballasts

1894 Daniel McFarlane Moore, a U.S. inventor produced the gas release lamp

using carbon dioxide and nitrogen to produce white and pink light respectively

1901: Serial inventor Peter Cooper Hewitt from New York, invented the mercury

vapour lamp. For the first time fluorescent lamps were being produced

commercially, albeit on a small extent

1926: Edmund Germer, Friedrich Meyer and Hans J. Spanner – all from Germany –

managed to produce a fluorescent tube with greater gas pressure and a fluorescent

inner coating that converted ultra violet light into visible white light.

1938: Having purchased the patent from Edmund Germer, General Electric mass

produced fluorescent lamps.

1974: GE Lighting invented the energy-efficient compact fluorescent bulb

How Does it Work?

First you need a glass tube that has small amount of a certain gas and some

mercury sealed inside – and nothing else. The gas will be argon or neon or any

of a number of other gasses (each produces its own rare colour). Electricity

is passed from one end of the tube to another. The electrons that pass by

ionise the atoms in the combination and cause it to release ultra violet light. The

electricity output must be limited before it can pass by, using a choke or

ballast. Without this limiting factor, fluorescent tubes could explode! By

contrast, a high voltage is required to get the whole course of action started. When the

lamp is first switched on, a starter is used to provide this

“kick-start”. The starter may be an integral part of the lamp build

and may be automatic or it may be a separate unit, typically a small plug that

twists into position.

The fluorescent lamp has had quite a journey from Jean Picard’s early musings

to the energy-efficient lamps of today. They are used in may applications. One

of these applications is the fly killer machine. Insectocutor fly killers use

ultra violet fluorescent tubes that attract flies in order to trap and kill

them. Each uv bulb comes complete with a starter and a choke.

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