Introduction to electronics

Can you even imagine what life would be like ... without smartphones? Just a few years ago a phone had no internet connection no colour screen. It couldn't even play music! And a few years before that... ...

you had to stay put in one place if you wanted to use the phone! Back then, you needed a lot of stuff to do all the things your phone lets you do today. Smartphones, and other electronics, have in many ways changed the way we live... ... and it all started with the radio... Just over one hundred years ago, inventors for the first time managed to send a message...

in the form of a radio wave through the air... ... that could be converted into sound! Music and speech, sent over long distances, without any wires? It was all quite miraculous. The first radio receivers required the listener to use headphones, as the signal was very weak.

Then came John Ambrose Fleming, and he made a discovery that would turn out to be important. He noticed that, if you take an ordinary light bulb, and add a second electrode to it, you will get a device capable of amplifying electric current. His invention -- the vacuum tube -- made it much nicer to listen to the radio... ... and soon, radio stations broadcasted all over the world. But the vacuum tube had more to offer than making radios sound better.

A vacuum tube doesn't only amplify an electric signal -- it can also function as a switch -- like a little gate -- that can be closed or opened, to let electrical current through. Before this time, electricity had mostly been used to transfer energy around. But with electronics, electricity began also to be used to transmit and process information. By carefully combining a range of vacuum tubes, using their ability to switch current on and off, electrical signals could be made to represent numbers. And this led to the first computer.

It took three years to build, used more than 17 000 vacuum tubes, and in 1946 it was finished: ENIAC. ENIAC performed mathematical calculations a thousand times faster than any other device could, at that time. And for that, it was nicknamed "Giant Brain" - which seems appropriate enough, since it weighed over twentyfive tons! To improve ENIAC, scientists looked for smaller and more durable vacuum tubes. But it wasn't a better type of vacuum tube that helped them.

It was the... transistor! A transistor does all that a vacuum tube does, but faster, cheaper, and more reliably. And it can be made much smaller. A transistor is made from a special type of material whose electrical conductivity lies in between a conductor and an insulator.

It's called: a semiconductor. Semiconductors are the basis for all modern electronics. By the 1970s, transistors were so small and cheap that thousands of them could be fitted onto one tiny chip of semiconductor material -- an integrated circuit. Since then, scientists have been able to fit more and more transistors onto each integrated circuit... ... the number of transistors on each chip has doubled every two years.

Today, integrated circuits are found in computers, medical equipment ... toys... refrigerators... ... and the device you are holding in your hand right now. In fact that device is more than one hundred thousand times more powerful than ENIAC was.

And very soon it too will be replaced.. by something even smarter and more powerful...