Transformers A transformer is an electrical device that takes advantage of inductance in order to convert one voltage/current to another voltage/current. The basic construction is shown in the figure to the right. Two coils of wire are wound around a frame that is highly permeable to magnetic flux—soft iron, for instance. The voltage fed into the primary side creates magnetic flux that is channeled around to the secondary coils, where induction occurs, converting the energy back to electricity. Clearly since this depends on inductance, a transformer will only work for AC . (This is why a cell-phone charger has the giant block on the end of the plug: The tiny wire leading away carries a small DC voltage, which means the transformer has to go right next to the AC wall outlet to step down the voltage there to a useful level there.) Remarkably, the transformer can be analyzed as a magnetic circuit where the flux Φ in webers takes the place of current, the driving (primary) coil provides a
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This note was uploaded on 04/05/2012 for the course PHYS 131 taught by Professor Tibbets during the Spring '11 term at Cuyamaca College.