ELECTRICAL TERMS:

In order to expertly diagnose electrical system troubles, the tune-up specialist must understand the electrical terms commonly used. So that a student can readily grasp the meaning of these terms, a water analogy is used, comparing the movement of electricity through a wire to the flow of water through a pipe.

CIRCUIT:  A circuit is a path through which current can flow, current flows through a circuit much like water flows through a pipe. The principle requirement of any circuit is that it must form a complete path. In tracing circuits, it is important to start at the source of electric power, either the battery or the insulated circuit, and return to the source through the ground circuit. A circuit is NOT complete if the current cannot return to its source.

A CONDUCTOR:   A conductor is a material that will pass electrical current efficiently just as a clean pipe is a good conductor for water. The ability of a conductor to carry current not only depends upon the material used but also on its length, its cross-sectional area and its temperature. A short conductor offers less resistance to current flow than a long conductor. A conductor with a large cross section will allow current to flow with less resistance than a conductor with a small cross section. For most materials, the higher the temperature of the material, the more resistance it offers to the flow of electrical current.

AN INSULATOR:  An insulator is a material that will not pass current readily. An insulator is used to prevent leakage of electrical current.

AN AMPERE:  An ampere is a unit of measurement for the flow of a quantity of electrical current. In terms of water analogy, this would be compared to gallons. The letter I is the symbol to represent the amperes.

A VOLT:  A volt is a unit of measurement of electrical pressure, or electromotive force. Voltage is sometimes described as a difference of potential between the positive and negative terminals of a battery or generator. In terms of water analogy, this pressure would be compared to pounds per square inch. In order for current to flow through a circuit, voltage must be applied to the circuit. The letter V is the symbol to represent the volts.

AN OHM:  An ohm is a unit of electrical resistance opposing current flow. Resistance varies in different materials and varies with temperature. In terms of water analogy, this resistance would be compared to a restriction in a pipe. The letter Ω is the symbol to represent the resistance.

A WATT:  A watt is a unit of electrical power, and is obtained by multiplying volts and amperes. As a point of interest, 746 watts are equal to one mechanical horsepower. The letter W is the symbol to represent the Watt.