Power Loss

• The advantage of alternating a current is that it allows use of transformers. The advantage of transformers is that transmission lines can have high voltage and, therefore, low power loss over long distances, while safer but less efficient voltage levels can be confined to the short lengths of power line to which the public is exposed.
  
  

Structure

• Step-up Transformer: n1/n2 = V1/V2
  
  A transformer consists of an alternating current, part of which coils around a magnetic core, usually of iron. The alternating current produces an alternating magnetic field. The core's changing magnetic field induces a current in the windings of another circuit.
  
  

Winding Count

• The difference in windings creates the change in voltage. If both coils are made of the same material and width, then the number of coil turns multiplied by the current through the coil is the same value for both.
  
  

Change in Voltage

• Because of energy conservation, the product of current and voltage is the same in both currents, thus the change in voltage is controlled by the winding count.
  
  

Current Transformer

• Current Transformer with Ammeter
  
  A current transformer measures the current of a circuit, which constitutes effectively a single winding through the magnetic core. The circuit with multiple windings has an ammeter attached. This configuration avoids exposing delicate instruments to damaging levels of current.