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24 Cards in this Set
- Front
- Back
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Voltage (E) |
The electric force of work required to move current through an electric circuit, measured in units of volts. |
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Volt (V) |
The unit of measurement of voltage in an electric circuit, denoted by the symbol V. |
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Current (I) |
The flow of free electrons in one general direction, measured in units of amps. |
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Amp (A) |
The unit of measurement of electric current, denoted by the symbol A. |
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Direct-Current (dc) |
Current that flows continually in one direction. |
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Alternating-Current (ac) |
Current that flows in a circuit in a pos- itive direction and then reverses itself to flow in a negative direction. |
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Resistance (R) |
The electrical “friction” that must be overcome through a device in order for current to flow when voltage is applied. |
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Ohm (Upside down horse shoe) |
The unit of measurement of resistance in an electric circuit |
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Inductance (H) |
The property that causes the current to lag the volt- age, measured in units of henries. |
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Capacitance (F) |
The property that causes the current to lead the voltage, measured in units of farads. |
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Energy (Wh) |
The amount of electric work (real power) consumed or utilized in an hour. The unit of measurement is the watt hour. |
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Power (P) |
The combination of electric current and voltage causing electricity to produce work. Power is composed of two components: real power and reactive power. |
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Volt-Ampere (VA) |
The unit of both real and reactive power in an electric circuit. |
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Real Power |
The resistive portion of a load found by taking the cosine () of the angle that the current and voltage are out of phase. |
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Watt (W) |
The unit of real power in an electric circuit. |
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Reactive Power |
The reactive portion of a load, found by taking the sine () of the angle that the current and voltage are out of phase. |
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Var (Q) |
The unit of reactive power in an electric circuit. |
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Power Factor (pf) |
The ratio of real power to reactive power. |
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Frequency (f) |
The number of complete cycles made per second, measured in units of hertz. |
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Hertz (Hz) |
Units of frequency (equal to 1 cycle per second). |
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Conductors |
Materials that have many free electrons and are good transporters for the flow of electric current. |
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Insulators |
Materials that have hardly any free electrons and inhibit or restrict the flow of electric current. |
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Series Resistive Circuit |
All of the resistive devices are con- nected to each other so that the same current flows through all the devices. |
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Parallel Resistive Circuit |
Each resistive device is connected across a voltage source. The current in the parallel path divides and only a portion of the current flows through each of the parallel paths. |
