We stayed at the Ski Station at the start of Glencoe, just round the corner from where they filmed for Skyfall. We found this transformer that steps down the voltage from 11000V for the Kingshouse Hotel. In the background is Buchaille Etive Mor, possibly the most photogenic mountain in Scotland.
This is the plate that tells you that it is 11kV.
Transformers are two coils wrapped around the same iron core. The primary coil acts as an electromagnet and magnetises the core. The mains electricity is alternating current, so the magnetic field in the core varies as well. This varying field induces a voltage (strictly an EMF) in the secondary coil. The size of this secondary output voltage depends on the ratio of turns between the two coils. In this case there will be a lot fewer turns on the secondary to reduce or step down the voltage to safer levels.
You can find out more about our electricity supply from this marvellous link: http://www.pylonofthemonth.org/
Pylon of the Month was one of the first things to "go viral" on the Internet around the Millennium. It has been revived by another Physics teacher. Respect!
