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| previously mentioned cycle of events will then reoccur until a new state of equalization will be reached. This new balance, it is obvious, can only be obtained by increasing the primary current. |

| The same chain of events is repeated in the reverse sequence when the load connected to the secondary coil is reduced. |

| Transformer Losses |

| All that has been said refers to an ideal or perfect transformer. In any actual instrument, the output is less than the input because of the transformer losses (heat developed in the wires and in the core). |

| Copper Losses |

| The heat losses developed in the wires are those caused by the resistance to the flow of current, which has been likened to the friction of water in a pipe, or friction between electrons moving in the conductor. This loss is determined by multiplying the square of the value of the current by the resistance (I2R). It must be emphasized that only the resistance, R, causes this effect. The inductance (usually denoted by the letter L) does not resist the flow of current, it prevents it from coming into being. Therefore, in determining the heat losses, only the resistance, R, is to be considered; the inductance, L (or inductive reactance, XL) and the impedance, Z, are not to be considered. It is obvious, too, that the greater the current flowing in the transformer (whether primary or secondary) the greater will be the heat (I2R) losses in the conductors of the coils. These losses are usually referred to as the copper losses in a transformer. |

| Hysteresis |

| If each molecule of the iron comprising the core of the transformer is considered as a minute magnet, then, as the magnetic field set up by an alternating current changes direction, these small magnets will reverse their position to accommodate the strong magnetic field. As these molecules change their position with each alternation of the magnetic field, friction between them is produced and energy is used up in overcoming it. This loss of energy due to friction between the molecules is given off as heat, and is called hysteresis. |

| Eddy Currents |

| The alternating magnetic field set up in a transformer not only induces voltages and currents in the coils through which it passes, but does so also in the core of iron. The currents thus induced in the iron core swirl around like |

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