There's a multitude of riches inside the calculator's case
From elements shared with a nuclear power plant to holding the secret of next generation energy production, your calculator is surprisingly well connected.
The nuclear connection
Indium, used in the construction of your calculator’s liquid crystal display (LCD), plays a big role in lots of electronic devices, but it’s more than a humdrum component.
In the calculator, compound indium tin oxide, is used to form the conductive transparent coating applied to touchscreens and is also found in semiconductors.
But indium takes on some rather more specialised roles too. In nuclear power plants, combined with silver and cadmium, indium makes up part of the control rods. Encased in steel, they help to control the rate of fission by absorbing neutrons. So you could say an element of your calculator also staves off meltdowns.
The fact that your calculator makes use of indium could also make it something of a rarity. Estimates based on the current stock of zinc ore – which provides one source of indium – suggest there could be as little as 13 years’ supply remaining.
Bullion behind the buttons
It won’t lead you to riches but there’s a small seam of gold within your calculator. Gold is a highly conductive material which makes it perfect for carrying the small amount of current produced by your calculator’s battery. It also doesn’t corrode easily, which makes it ideal for coating crucial connectors, switches and relays.
While it is possible to strip gold from electronic components and sell it, the quantity you’d get through dismantling your calculator is miniscule. There’s around 35p worth in there, so unless you have a serious calculator collection, it’ll be a while before you’re a recycling millionaire.
A plastic bottle reborn
Some new calculators (like the Sharp Eco-concept range) feature casings derived from post-consumer recycled plastic. That means they’ve had a past life as discarded waste. One of the most common sources is plastic bottles, so that discarded drink on your desk could soon be on its way to becoming your next calculator.
You can also recycle your calculator when you’re done with it, but you’ll need to dismantle it first to separate some of the non-recyclable internal parts from the plastic casing. For most calculators that simply means undoing some screws.
The key to a solar powered future
If your calculator has a solar panel, it uses amorphous silicon. Until recently, calculators were really the only place where it was used commercially. At larger sizes, it was considered inefficient. But researchers have begun to overcome those limitations and its strengths could put it at the heart of the next generation of solar panels heading for a roof near you.
See, amorphous silicon cells can be made thinner than other formulations of silicon. They can also be stacked up, one on top of the other. That means several thin amorphous silicon solar cells could be combined, with each one tuned to a specific light frequency. Constructing solar cells this way uses around 1% of the silicon, and considerably less energy, than needed for a typical crystalline silicon cell today.
