Low Frequency Power Transformers are used to step down mains voltage of 230V or 110V to safer voltages like 12V and 6V. The core is made of laminations of a Conditioned Alloy of Iron. The windings are Enameled or Insulated Copper Wire. They provide both Isolation and Safety while Scaling the Voltage and Power.
Mains Power Packs with 50Hz Transformers are still popular for audio and some product safety sensitive applications, as they are more isolated, reliable and EMI-RFI free.
Power Supplies Section – ideas on how Transformers are used in making Power Supplies and Battery Chargers.