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33 Cards in this Set
- Front
- Back
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Electric Circuit |
Electricity being controlled and often converted to other forms of energy. |
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What three things does an electric circuit consist of? |
(1) a power source. (2) connecting wires, or conductors. (3) a device that uses the electrical energy of the source to accomplish some purpose. |
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Load |
Device that uses the electrical energy |
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Open Curcuit |
When a complete path does not exist, no current will flow |
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Voltage source |
Source producing EMF which is measured in volts |
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Voltage source |
Source producing EMF which is measured in volts |
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Direct current |
The current flow in a circuit will always be in the same direction if the polarity of the source voltage always remain same |
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Alternating Current |
When the voltage polarity of the power source changes or alternates the direction of the current flow will also alternate |
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What factors determine how much current will flow in a D-C circuit? |
(1) the amount of voltage that is supplied by the power source (2) how well the load and wires conduct current |
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What factors determine how much current will flow in a D-C circuit? |
(1) the amount of voltage that is supplied by the power source (2) how well the load and wires conduct current |
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Conductance |
The ease with which a metal allows current to flow |
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Resistance |
(1) The opposition or resistance to the flow of electrons (2) Depends on the number of free electrons the material has |
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Resistance |
(1) The opposition or resistance to the flow of electrons (2) Depends on the number of free electrons the material has |
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1 Ampere |
6,280,000,000,000,000 free electrons passing any given point in wire in 1 second |
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Is the resistance lower or higher if the cross sectional area of a wire is greater? |
Lower |
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Doubling the length of a wire causes what? |
It doubles the resistance, because of the relationship we say that the resistance of a wire directly proportional to its length |
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If you double the cross-sectional area of a wire what will happen? |
You will halve the resistance, we can say that the resistance of a wire is inversely proportional to its cross-section |
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Temperature coefficient |
The amount that the resistance is affected by each degree of temperature change |
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Positive temperature coefficient |
When a materials resistance goes up as temperature is increased |
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Negative temperature coefficient |
When a materials resistance goes down as temperature is increased |
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Ohm |
Unit of resistance |
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Safe limit |
The maximum current a source can supply before they burn out |
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Internal resistance |
A resistance that every source has that opposes current flow |
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Internal resistance |
A resistance that every source has that opposes current flow |
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American Standard Wire Gauge |
Dimensions and typical resistances of commercial copper wire |
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Composition Resistor |
Consists essentially of a powdered carbon resistance element, and wire leads for connecting the resistor into a circuit |
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Composition Resistor |
Consists essentially of a powdered carbon resistance element, and wire leads for connecting the resistor into a circuit |
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Wirewound Resistors |
A resistor that has wire wound around its core |
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Power Wirewound Resistor |
Used for circuits having large currents |
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Precision Wirewound Resistor |
Used when resistances with very small tolerances are required |
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Film Resistors |
Considered a compromise between composition and precision type Wirewound Resistors. They have some of the accuracy and stability of the Wirewound type, but are smaller, more rugged, and cheaper |
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Power |
The emoting of work that can be done by a load in some standard amount of time, usually one second |
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Dissipated |
When power is used for wasted work |
