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21 Cards in this Set
- Front
- Back
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One kilowatt is equal to how many watts ? |
1,000 watts |
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What law describes the most fundamental or basic relationship in an electrical circuit ? |
Ohm's law |
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What are three elements of Ohm's law ? |
Voltage, current and resistance. |
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How would you write Ohm's law as an equation ? |
E= I x R, R= E ÷ I, I = E ÷ R. |
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If the resistance in a DC circuit remains the same but the voltage doubles, what happens to the amount of current flowing in the circuit ? |
It also doubles. |
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In DC circuits, what unit measures power ? |
Watts |
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What three elements are required to form an eletrical circuit ? |
A source of electrical energy A load or resistance to use the electricity And wires or conductors to connect the source to the load. |
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DC circuits can take one of three forms or types. What are they ? |
Series, parallel, and complex (series-parallel). |
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A 24-volt lead-acid battery has how many cells ? |
Twelve-12. |
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A fully charged lead-acid battery has a specific gravity that varies between what two values ? |
1.275 and 1.300 |
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You must apply a correction to the specific gravity reading of the electrolyte of a lead - acid battery when the temperature is outside of what values ? |
Whenever the temperature is less than 70°F or more than 90°F. |
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What is the reason for having separarte facilities for storing and servicing nickel-cadmium and lead-acid batteries ? |
The electrolyte in the two types of batteries is chemically opposite and the fumes from one type can contaminate the electrolyte of the other type. |
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The state of charge of a nickel-cadmium battery cannot be determined by measuring the specific gravity of the electrolyte for what reason ? |
There is no significant change in the specific gravity of the electrolyte as the battery is charged or discharged |
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What is the principal advantage of AC current over DC current ? |
Power can transmitted over long distances more efficiently and with smaller wires because the voltage can be easily increased or decreased by a transformer. |
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What are the three causes of opposition to current flow in an AC circuit ? |
Resistance, inductive reactance and capacitive reactance. |
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Define inductance. |
An induced voltage which is opposite in direction to the applied voltage. |
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What component creates capacitance in AC circuit |
A capacitor. |
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How does a capacitor store electricity ? |
The energy is stored in the form of an electrostatic charge or field that exists between two conductors separated by an insulator. |
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What property of an AC circuit is defined by the term "impedance" ? |
The total opposition to current flow. |
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What are two reasons that might cause a nickel-cadmium battery to fail to deliver its rated capacity ? |
Faulty cells or cells imbalance. |
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What electrical values are measured by a typical multimeter ? |
Voltage, current and resistance. |
