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35 Cards in this Set
- Front
- Back
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What is the basic unit of voltage? |
The Volt |
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What is the basic unit of current? |
The Amp |
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What is the basic unit of resistance? |
The Ohm |
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Which law of electricity is the most important for an aircraft mechanic to know? |
Ohm's Law |
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What are the three elements in Ohm's Law? |
Volts, Amps, and Ohms |
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What are five sources of electrical energy? |
Chemical, magnetic, heat, light, and pressure. |
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What four things affect the resistance of an electrical conductor? |
Material, cross sectional are, length and temperature. |
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How can you tell the resistance of a composition resistor? |
By the colored bands around one end of the resisitor. |
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What three things must all electrical circuits contain? |
Source of electrical energy, a load, and a conductor to join the source of energy and the load. |
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What is the purpose of a capacitor? |
To store electrical energy in electrostatic fields. |
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What is the basic unit of capacitance? |
The Farad |
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Why should electrolyte capacitors not be used in an AC circuit? |
Because they are polarized, they will pass current of one polarity but block current of the opposite polarity. |
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What is meant by inductance? |
Ability to store energy in electromagnetic fields. |
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What is the basic unit of inductance? |
The Henry |
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What is meant by impedance? |
The total opposition to the flow of AC current. It is the sum of resistance, capacitive reactance, and inductive reactance. |
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How can you find the polarity of an electromagnet? |
Left hand rule. Thumb will point to the north end of the electromagnet. |
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In what unit is impedance measured? |
Ohm's |
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What is the basic unit of electrical power in a DC circuit? |
The Watt |
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What is meant by a kilowatt? |
1,000 Watt's |
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What happens to the current in a DC circuit if the voltage is increased but the resistance stays the same? |
The current increases. |
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What are three types of DC circuits, with regard to the placement of the various circuit components? |
Series, Parallel, and Series-Parallel |
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How many cells are in a 24 volt lead acid battery? |
12 cells. |
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What is the specific gravity of the electrolyte in a fully charged lead acid battery? |
Between 1.275 and 1.3 |
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What is the range of temperatures of the electrolyte in a lead acid battery that does not require that you apply a correction when measuring its specific gravity? |
Between 70°-90° F. |
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What instrument is used to measure specific gravity of the electrolyte in a lead acid battery? |
A Hydrometer. |
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How is a lead acid battery compartment treated to protect it from corrosion? |
Paint it with tar based paint or polyurethane enamel. |
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What is used to neutralize spilled electrolyte from a lead acid battery? |
Solution of bicarbonate soda and water. |
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How high should the electrolyte level be in a properly serviced lead acid battery? |
No higher than the level indicator in the cell. |
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What precautions should be taken in a maintenance shop where both lead acid and nickel-cadmium batteries are serviced? |
Batteries should be kept separate and tools used on one type should not be used on the other. |
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Why is a Hydrometer not used to measure the state of charge of a nickel-cadmium battery? |
Its specific gravity doesn't change appreciably. |
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What is used to neutralize spilled electrolyte from a nickel-cadmium battery? |
Solution of boric acid and water. |
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What is meant by electromagnetic induction? |
The transfer of electrical energy from one conductor to another without being electrically connected. |
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How many ohms are in a megohm? |
1 million |
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What part of an amp is a milliamp? |
0.001 (one thousandth) |
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What is the principal advantage of AC current over DC current? |
The voltage can be easily increased or decreased by a transformer. |
