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| DIRECT CURRENT | abbreviated DC, current which flows in one direction. A battery produces DC |
| ALTERNATING CURRENT | abbreviated AC, current which alternates direction, constantly switching back and forth. An electrical power outlet supplies AC. |
| CIRCUIT | a path for current to flow in a continuous loop, usually including a power source, wires, and components such as lamps, motors and so on. |
| SERIES CIRCUIT | a circuit in which all the current flows in a single path through every component in succession. |
| PARALLEL CIRCUIT | a circuit in which there are multiple current paths, with some of the total current flowing through each path at the same time. |
| CLOSED CIRCUIT | a conductor arranged in a continuous loop in which current can flow |
| OPEN CIRCUIT | a circuit which has been broken, preventing current from flowing. |
| SHORT CIRCUIT | a circuit with a very low-resistance path that shunts current directly across the power source, preventing electricity from reaching its intended destination and often resulting in excessive current. |
| SWITCH | a device which allows the user to conveniently create a closed or open circuit as desired. |
| GROUND | a common electrical reference for all the circuitry in a system, against which all voltages are measured. “Ground” is defined as zero volts, whatever its absolute charge may be. |
| EARTH GROUND | a ground electrically connected to Earth |
| EQUIPMENT or SYSTEM GROUND | a ground reference within a system, which may or may not be Earth-grounded. |
| WIRE GAUGE | thickness of a wire; smaller numbers indicate larger diameter. |
| FUSE | an undersized wire, contained in a small enclosure, that's designed to melt and open a circuit before the rest of the system overheats and starts a fire. Fuses are rated by current. |
| NATIONAL ELECTRICAL CODE – | published by the National Fire Protection Association, the universal reference for electrical safety standards. |
