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Two years ago we changed all the halogen ceiling lights in our home to light emitting diodes (LEDs). What joy! Our LEDs are brighter than the lights they replaced, they use less electricity, they mimic the colour of sunlight, they have not visibly aged since they were installed, they work with dimmers and they are safer in the ceiling cavity because they do not run nearly as hot as the halogens.

Like a distant uncle I have watched LEDs grow up from a tiny plaything to the workhorse of modern lighting.

I was too young to appreciate them when the first commercial LEDs were released in 1962, but by the early 1970s I was assembling electronic gadgets out in the garage, where I kept red LEDs about half the size of a pea as part of my stock of electronic components. I still have an ornament I made that consisted of LEDs mounted on the tip of long plastic wires like red eye stalks, each blinking to its own private rhythm.

Sometime around then I purchased my first digital watch, the amazing Pulsar with numbers made up of tiny LED dots.

Later, as an engineer in a company designing scientific research apparatus, I used LEDs as front-panel indicators. They were barely visible in a brightly lit room so for anything important we used incandescent bulbs.

During the 1970s and 1980s, LEDs gradually became brighter and red was joined by amber, green and eventually blue in the mid-1990s, at which point LEDs replaced incandescent lamps as indicators on panels fronting appliances from ovens to audio amplifiers.

LEDs last for many years, even when heavily used, partly because they are “cold” light sources in which the light emission is a subatomic process that does not rely on heat.

In contrast, in a halogen or conventional incandescent bulb, the light comes from the glow of a tungsten filament heated to white hot. At those temperatures the filament slowly vaporises, hence their relatively short life.

This year’s Nobel Prize for physics was awarded for the invention of the blue LED (see A blue light that might save the world). Blue LEDs are essential for the use of LEDs in television screens and ceiling lamps.

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Growing up as LED lights come of age