 welcome to opens and shorts. Two common conditions that cause an electrical circuit to become defective are opens and shorts. An open produces an infinite resistance. A short produces zero resistance. An open is a circuit condition in which the current path is broken so that there is no current. Examples of an open condition follow. The filament of a light bulb is burned out which opens the path to current flow. The wire becomes disengaged from a wire nut and breaks the circuit path. The pin of an integrated circuit chip becomes bent and does not make electrical contact with the printed circuit track. Other examples of open conditions are a crack in a printed circuit board inside a television expands and contracts due to the fluctuation between hot and cold when it is turned on and off. The breakage of a mechanical mechanism inside a switch prevents two contacts from physically touching. And the continuous vibration of the road causes a wire inside an automobile cable harness to break. The problem may be intermittent which means continuous vibration may cause the breaks to alternately separate and join together. A short is a zero or normally low resistance between two points of a circuit. It usually causes resistance in a circuit to be bypassed thus causing current to increase. Examples of shorted conditions on a printed circuit board are solder splash and wire clipping. See how the bypass resistors are shorted. Shorted leads. When a shorted condition like this develops the current bypasses the resistors because it takes the path of least resistance. The increased current can cause a protection device such as a circuit breaker or fuse to break the circuit path and stop current flow. Other examples of a shorted condition are the insulation from a plug being pulled back because it is removed from the outlet by grabbing the wire thus causing two bare wires to touch. And the breakage of a mechanical mechanism inside a switch that prevents two contacts from physically separating. Let's try a few questions. A shorted condition A is an interruption of current flow or B causes excessive current. The answer is B causes excessive current. An open condition is A an interruption of current flow or B causes excessive current. The answer is A is an interruption of current flow. A solder splash creates a short or an open. The answer is A a short. A crack in a circuit board creates A an open, B a short, C either A or B. The answer is A an open. Wire clippings connected to two sections of a circuit can cause what first and then what by tripping a fuse. Wire clippings connecting two sections of a circuit can cause a short first and then an open by tripping a fuse. An intermittent fault is one in which the circuit condition is A permanently defective or B alternates between being defective and operating properly. The answer is B alternates between being defective and operating properly. You have completed this activity opens and shorts.