It may look like nothing more than a bit of metal with legs, but the humble transistor is responsible for the function of every single modern electronic device you own. It's such an integral part of our technological world that we are surrounded by hundreds of trillions of them on a daily basis.

Rewind to 1947 when three American physicists at Bell Telephone Laboratories - John Bardeen, William Shockley and Walter Brattain - unveiled their groundbreaking transistor to the world. Nine years later, it had earned them the Physics Nobel Prize. Now it is estimated that there will be 1,200 quintillion transistors in the world by the year 2015, and demand will keep on growing as new technology is released.

Simply put, it’s a semiconductor device that can power electrical signals on and off, allowing silicon chips and circuits to function at lightning speeds. Over the years, transistor size has progressively shrunk, with the smallest now measuring between five and 10 atoms.

According to Moore’s Law, the number of transistors added to integrated circuits in the technology we so heavily rely on doubles every year, so while a quad-core i7 processor produced in 2010 used 1,170,000,000 transistors to power your new laptop, the updated Sandy Bridge i7 processor of 2011 had ramped up the number of transistors to a staggering 2,270,000,000 embedded in a processor measuring just 216mm square. While Moore’s Law is progressively slowing and could well be defunct by 2020, it shows just how imperative the transistor is to our daily lives.

Where the first portable devices such as early radios and calculators came with five to 10 transistors, an iPod now has a staggering 256 billion transistors installed and a Kindle over 16 billion.

But how does all this progress affect us? Well, it means that processing power just gets quicker and quicker, making tech appliances such as our computers mind-bogglingly fast.

Ultimately, the transistor’s success is down to its simplicity and ability to be mass-produced cheaply. If the first transistor hadn’t taken the world by storm, the first computers occupying entire rooms would still be the norm, working on leaky vacuum tubes that hog space and energy.

Widely regarded as one of the greatest inventions in the last 100 years, we can thank the transistor for pretty much every electrical item we own. It’s true; the simplest innovations are the best.