Transformers; Generating and Transmitting Electric Power
How a coil of wire changes voltage, and how power travels hundreds of kilometres from a mountain dam to your home
Big idea: A transformer uses a changing magnetic flux shared between two coils to raise or lower an alternating voltage without moving parts. This single trick makes the whole power system possible: generators produce electricity, transformers step the voltage up so it can travel long distances with tiny losses, and other transformers step it back down to a safe value for homes and schools.
By the end you will be able to:
- explain how mutual induction lets a transformer change voltage, and why it needs alternating current;
- use the transformer equation U1/U2 = N1/N2 and the ideal-power relation U1I1 = U2I2;
- describe how an alternating-current generator turns mechanical rotation into EMF;
- explain why electric power is transmitted at high voltage, using Ploss = I2R;
- outline the route power takes from the Toktogul hydroelectric station to a consumer.