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  • Transformers
    • How does it work?
      • 1) Alternating current passes through the primary coil
      • 2) This produces an alternating magnetic field in the core
      • 3) The moving magnetic field in the core passes the secondary coil and induces (ie generates) an electrical current in it.
      • 4) If both coils are the same and no energy is lost, you get out exactly what you put in.
      • 5) If however there are more coils on the output (or secondary) windings, the voltage is stepped up
      • 6)  With less coils on the secondary than the primary the output voltage is stepped down.
      • 7)  The RATIO of the number of coils determines the RATIO of the input and output voltages
      • 8)  So if the voltage goes up the current goes down by the same ratio and vice versa
    • Uses of Transformers:
      • The National Grid
    • Step-up and Step-down transformers
      • A transformer that increases the voltage is called a step-up transformer
        • Step-up transformers have more turns on the secondary coil than they do on the primary coil.
      • A transformer that decreases the voltage is called a step-down transformer
        • Step-down transformers have fewer turns on the secondary coil than they do on the primary coil.
    • A transformer is an electrical device that changes the voltage of an AC supply. A transformer changes a high-voltage supply into a low-voltage one, or vice versa.
      • Transformers only work if AC is supplied to the primary coil. If DC was supplied, there would be no current in the secondary coil.
    • The ratio between the voltages in the coils is the same as the ratio of the number of turns in the coils.
      • primary voltage / secondary voltage = turns on primary / turns on secondary
      • Vp/Vs = Np/Ns


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