The hope of transmitting electrical power has fascinated scientists for years. One of the first major breakthroughs came when Nicola Tesla proposed theories or wireless power transmission and proved his point by wirelessly powering the lights around his Colorado Springs laboratory! Whilst long distance wireless electricity is still an impossibility, this technology is right under your nose (well at least twice a day). Electric toothbrushes utilize this technology. Because there is a lot of water involved it’s not really a great idea to have a toothbrush plugged into the mains, and a regular charging station would have exposed metal work that would be corroded easily by the water in a bathroom environment. So the way this problem was solved was by using wireless electricity to charge the battery inside the toothbrush. In simple terms whenever an electrical current moves through a wire it creates a magnetic field around it, and if you loop the wire around itself, like a spool of cotton it will increase this magnetism. If you put two of these spools together and pass a current through one then the current from the live spool will ‘jump across’ to the other, this method is known as inductive coupling and it is how to transmit an electric current wirelessly. Although the transmission distant is short it has already been developed as a means to charge up appliances. For example you can now get charging mats which will charge up your phone or mp3 player by simply placing the product on them.
Spinning Discs to kWh…..how does that work?
Electric meters are everywhere. In every part of the modernized world where you find power networks you’ll find an electric meter. These meters are used to measure the amount of electricity you are using. I’m going to try to explain how to read electric meter but first I’ll explain how they work.
Inside the unit is a spinning disc. The speed of this disc is determined by how much electricity you are using – the more you use the faster it goes. This disc drives gears that rotate at different speeds. These discs are usually mounted vertically in a sequence with number on the side. On the cover of the electric meter is a small display window, through this window these numbers can be seen. These numbers show the cumulative consumption over time. The number of rows changes from country to country but most of them are counting the same thing…..kilowatts per hour (kWh). It’s from this measurement that your electricity supplier can work out how much he will charge you. How the numbers are displayed are also different from unit to unit, but the most common are a straight row of numbers or a row of dials. The row of numbers are fairly easy to read, all you have to remember is to read from left to right and that the value on the furthest right is usually ignored as it is measuring 100 watts and not Kilowatts (1000watts). So now you know how to read an electric meter!