About this blog

Physics can be difficult to learn, but this blog aims to help you get into physics by connecting your GCSE physics lessons with things you see in the world around you.

Thursday, 27 October 2011

One Way Street

I’m a fan of walking, but as such that means that I’m very often crossing the road. Now you’d think that the main danger would be cars, but it’s not! It’s bikes. It’s very rare you see a car going down a one way street the wrong way. And if they do, it’s very often with a look of cringing embarrassment with a side of well-I’m-pointing-this-way-now!

Bikes on the other hand are a different matter. They go everywhere, whether it’s the wrong way down a one way street or not, regardless of how many half asleep people there are making their way to work! Now if only there was a better way of making sure that people didn’t do things like that than just putting up signs.

If only there were diodes for people. Diodes are an important electronic component, and they work by only letting electrons flow through them in one direction, so they are effectively a one way street for electrical current. This means that you have to insert them into your circuit the right way round, otherwise it will never work!

You can see from the electrical symbol for the diode which way it works, and when you see a diode, there is a flat side to it that corresponds with the flat side of the triangle, or a direction written on it. Diodes work by having a very low resistance in the correct direction, and a very high resistance in the opposite direction. These days, the type of diode most commonly found is the light-emitting diode, normally shortened to LEDs:

Ah, you say, LED TVs are the next big thing! So now you know that inside these new pieces of technology are lots of diodes, whose one-way system I would like to borrow for our streets!

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