General Oral Flashcards
What constitutes a capacitor?
Two conductors separated by an insulator
What is the purpose of a capacitor?
Stores electrical energy
What is the basic unit of capacitance?
The farad
Why should electrolytic capacitors not be used in an AC circuit?
They are polarized / passes current of one polarity but will block opposite polarity
What is meant by inductance?
Ability to store electrical energy in electromagnetic fields
What is the basic unit of inductance?
The henry
Does a capacitor in an AC circuit cause the current to lead or lag the voltage?
Lead
Does an inductor in an AC circuit cause the current to lead or lag the voltage?
Lag
What is the basic unit of power in a DC circuit?
The watt
What happens to the current in a DC circuit if the voltage is increased but the resistance remains the same?
It increases
What are five sources of electrical energy?
Magnetism, Chemical energy, light, heat and pressure
Which law of electricity is the most important for an aircraft mechanic to know?
Ohms law
What are the elements of ohms law?
Voltage, Current and Resistance
What is the name of the law that describes the relationship in an electrical circuit of voltage, current and resistance?
Ohms law
What is the basic equation of Ohms law?
E= I x R
What is the formula for determining power?
P= I x E
What is meant by a kilowatt?
1,000 watts
What is meant by a magawatt?
1,000,000 watts
What instrument is used to measure current flow?
Ammeter
What is a megohm?
One million ohms
What instrument is used to measure electrical resistance?
ohmmeter
When measuring resistance of a component with an ohmmeter should the circuit be energized?
No
What instrument is used to measure continuity in an electrical circuit?
Ohmmeter
What units is battery capacity expressed?
Ampere hours
What instrument is used to measure the specific gravity of the electrolyte in a lead acid battery?
Hydrometer
What is voltage?
Electrical pressure
What is the basic unit of voltage?
The volt
What instrument is used to measure voltage?
Voltmeter
To measure voltage is a voltmeter placed in series or in parallel with the source of voltage?
Parallel
What is the voltage across each resistor connected in parallel across a 12 volt battery?
12 volts
What is the open-circuit voltage of a lead acid cell?
2.1 volts
How is output voltage regulated in an AC alternator?
Varying the strength of the AC exciter fields
What is electrical current?
Flow of electrons in a circuit
What is the basic unit of current flow?
The amp
What two things happen when current flows through a conductor?
Heat is generated and magnetic field surrounds conductor
To measure current through a component is an ammeter placed in parallel or in series with the component?
Series
What is meant by resistance in an electrical circuit?
Opposition to flow of electrons
What is the basic unit of electrical resistance?
The ohm
What four things affect the resistance of an electrical conductor?
Material, cross section area, length and temperature
How can you tell the resistance of a composition resistor?
Colored band
What is meant by impedance?
Total opposition to flow of alternating current
In what units is impedance measured?
Ohms
What is the relationship between mechanical and electrical power?
1 horsepower = 746 watts
What units is true power expressed?
Watts
In what units is apparent power expressed?
Volt-amps
What is meant by the capacity rating of a lead acid battery?
Number of hours a battery can supply a given current flow
What electrolyte is used in a lead acid battery?
Sulfuric acid and water
Does the specific gravity of the electrolyte in a lead acid battery increase of decrease as the battery becomes discharged?
Decreases
What is specific gravity of a fully charged lead acid battery?
Between 1.275 and 1.300
How many cells are there in a 24 volt lead acid battery?
12
What is the range of temperature of the electrolyte in a lead acid battery that does not require correction when measuring its specific gravity?
Between 70F and 90F
How do you treat a lead acid battery compartment to protect it from corrosion?
Paint with asphaltic paint or with polyurethane enamel
What is used to neutralize spilled electrolyte from a lead acid battery?
Baking soda and water
How high should the electrolyte level be in a properly serviced lead acid battery?
Only up to level of indicator in the cell
What gasses are released when a lead acid battery is being charged?
Hydrogen and oxygen
What is the electrolyte used in a nickel cadmium battery?
Potassium hydroxide and water
Why is a hydrometer not used to measure the state of charge of a nickel cadmium battery?
Specific gravity does not change
Is the electrolyte level of a nickel cadmium battery lowest when the battery is fully charged or fully discharged?
Fully discharged
What is used to neutralize spilled electrolyte from a nickel cadmium battery?
Boric acid and water
What three things must an electrical circuit contain?
Source, load and conductors
What is the basic function of a switch?
Controls current flow
What is a relay?
Electromechanical switch
What are the two main types of variable resistors?
Rheostat and potentiometer
What type of drawing depicts electrical components with respect to each other within a circuit?
Electrical Schematic
What are three types of DC circuits with regard to the placement of the various circuit components?
Series, Parallel, and series parallel
What are two general types of AC motors used in aircraft systems?
Induction motors and Synchronous motors
What are two principal parts of a DC motor
Field assembly and armature assembly
How many views can there be on an orthographic projection?
Six
How many views are used to show the objects in an aircraft drawing?
Three
What information is given in the title block of an aircraft drawing?
Name and address of company, name of part, scale of drawing, name of draftsman, name of engineer and the number of the part
Where is the title block normally located on an aircraft drawing?
Lower right hand corner
How can you know that the aircraft drawing you are using is the most current version of the drawing?
The number in the revision block
What is a detail drawing?
Drawing that includes all information to fabricate the part
What is an assembly drawing?
Drawing that shows all components of a part in an exploded form
What is an installation drawing?
A drawing that shows location of parts and assemblies on the complete aircraft
What type of drawing is most helpful in troubleshooting a system?
schematic diagram
What is a block diagram?
Shows various functions of a system by a series of blocks
How are dimensions shown on a aircraft drawing?
Numbers shown in the break of a dimension line
What is the purpose of a center line on an aircraft drawing?
Divides a part into halves
What is the purpose of a sketch of a repair?
Shows specific information and includes minimum amount of detail needed to create the part
Where would an aviation mechanic find aircraft electrical schematics?
Maintenance manual or Wiring diagram
What is a fuselage station number?
Distance in inches from datum
What is a butt line?
Reference line to the right or left of the center line of aircraft
What is meant by tare weight?
Weight of any chocks and other items that are used on scales
What is included in the empty weight of an aircraft?
Weight of airframe, engines and all items of operating equipment that are permanently installed
What equipment must be installed in an aircraft when it is weighed to find its empty weight center of gravity?
All equipment listed in the Aircraft Equipment list as required equipment or as equipment that is permanently installed
What is meant by permanent ballast for an aircraft?
Weight that is permanently installed in an aircraft
What is meant by the maximum zero fuel weight of an aircraft?
The maximum permissible weight of a loaded aircraft
What is meant by undrainable fuel?
Fuel left in tank after it is drained