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Page 13

| Figure 1-13 Water analogy of resistance and reactance relationship to impedance. |

| Resistance and reactance are not added directly to arrive at the impedance of the circuit. Rather, their relationship may be compared to a boat traveling in a body of water affected by both current and wind (Fig. 1-13); it is pushed by the current (resistance) of the water, and by the wind (reactance). If the wind in one direction is at right angles to the boat, it may be referred to as inductive reactance; if in the other direction, it may be referred to as capacitive reactance; the net effect of the two is the overall reactance. The relative strengths of these three components will determine the direction the boat would take; similarly, the relative position of the current wave with respect to the voltage wave will be determined by the relative values of the three components of impedance: resistance, inductance, and capacitance of the circuit. It is obvious that if the inductance and capacitance values are equal, then the net reactance is equal to zero and the only quantity left is resistance. When this condition occurs, the circuit is said to be in resonance. |

| Generation of Voltage in a Transformer Coil |

| It has been demonstrated how an electrical pressure or voltage may be generated in a conductor adjacent to another one carrying an alternating current. This process is called induction, and, in the conductors it acted to obstruct the normal flow of current. This same effect of induction, however, can prove useful in another way. |

| Instead of two wires adjacent to each other, assume there are two coils of wire adjacent to each other and an alternating current of electricity flows in one of them. As was shown previously, the voltage induced in the second coil will depend on the length of the conductor, the relative speed between conductor and the magnetic field, and the strength of the magnetic field. The entire magnetic field set up by the first coil can be assumed to cut the turns of the second coil if both coils are wound on an iron core (Fig. 1-14 on page 14). The relative speed between the conductor and magnetic field is fixed, being dependent on the frequency of the alternating current flowing through the first coil. The voltage in the second coil will therefore depend on the length of the conductor, or on the number of turns. If the magnetic field and the rate of |

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