I have just finished my new book "Eureka!". It is all about thosedramatic moments in history when a new product or process was first discovered(if you want a copy please email me at VernonStent@hotmail.com) . One of the inventions that did not makeit into the book was the fluorescent lamp (or tube). That is not to say it isn'ta 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 neverreally invented at all but that it evolved over time.
The creation of the fluorescent lamp was a truly joint effort spanning acentury: Here are the milestones:
1675: Jean Picard, a French astronomer, noted that mercury in a barometertube would glow when shaken. He recorded this observation but did not understandit
1846: Julius Plücker, German mathematician and physicist, theorized andexperimented with coloured light produced by passing electricity through variousgasses. He worked with glassblower Heinrich Geissler who invented what was tobecome 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 electricdischarge 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 lightusing high frequency lighting ballasts
1894 Daniel McFarlane Moore, a U.S. inventor created the gas discharge lampusing carbon dioxide and nitrogen to produce white and pink light respectively
1901: Serial inventor Peter Cooper Hewitt from New York, invented the mercuryvapour lamp. For the first time fluorescent lamps were being producedcommercially, albeit on a small scale
1926: Edmund Germer, Friedrich Meyer and Hans J. Spanner - all from Germany -managed to produce a fluorescent tube with greater gas pressure and a fluorescentinner coating that converted ultra violet light into visible white light.
1938: Having purchased the patent from Edmund Germer, General Electric massproduced 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 somemercury sealed inside - and nothing else. The gas will be argon or neon or anyof a number of other gasses (each produces its own unique colour). Electricityis passed from one end of the tube to another. The electrons that pass throughionise the atoms in the mixture and cause it to emit ultra violet light. Theelectricity output must be limited before it can pass through, using a choke orballast. Without this limiting factor, fluorescent tubes could explode! Bycontrast, a high voltage is required to get the whole process started. When thelamp is first switched on, a starter is used to provide this"kick-start". The starter may be an integral part of the lamp buildand may be automatic or it may be a separate unit, typically a small plug thattwists into position.
The fluorescent lamp has had quite a journey from Jean Picard's early musingsto the energy-efficient lamps of today. They are used in may applications. Oneof these applications is the fly killer machine. Insectocutor fly killers useultra violet fluorescent tubes that attract flies in order to trap and killthem. Each uv bulb comes complete with a starter and a choke.
Here you can see the Insectocutoruv bulb range and here and here you can see lampstarters.