Magnetism

Current flow through the total parallel circuit will be equal to the current flow through any individual series circuit component. The disconnection or the burning out of the series components will completely disable the entire circuit, whereas a failure of any of the parallel circuit components will leave the balance of the circuit still functioning. Short circuit (fig. 1-14, view B). A short circuit occurs when copper touches copper, such as when wiring insulation between two wires fails and the wiring makes contact. REVIEW 3 QUESTIONS Q1. Voltage is known by what term? CIRCUIT FAILURES Open circuit (fig. 1-14, view A). An open circuit is a break or interruption in the circuit, such as a wire that has come loose or a slipped connection that is not making contact. But the expression of an open circuit is not only used when wire connections are actually separated as in a switch but also when the resistance in the wiring circuit is so that no current can flow between the battery and the unit it operates. A good example of such a condition is rust and corrosion that forms and accumulates at a battery cable or terminal. Ground circuit. A ground circuit occurs when any part of the wiring circuit is touching the vehicle frame inadvertently. A ground involves accidental or unintentional contact between copper and the iron frame. Q2. What are the three basic types of electrical circuits? Q 3 . What type of circuit failure occurs when copper touches copper? MAGNETISM Learning Objective: Describe the theory ofmagnetism and the principles of electromagnetism and electromagnetic induction. Magnetic field is described as invisible lines of force which come out of the North Pole and enter the South Pole. For example, if iron filings were sprinkled on a piece of glass on top of a bar magnet, the filings would form themselves in curved lines Figure 1-14.—(A) Open circuit; (B) Short circuit. 1-12