NCATT (AET)
Ampere ( A, amp, amperage) - answer• Unit of measurement used to express the flow
of electrons (electrical current)
• One ampere is a rate of flow of one coulomb (6.28 billion - billion electrons) passing a
given point in an electrical circuit per second
• In mathematical problems amperage is expressed by the letter "I"
Battery - answer• A device consisting of a number of primary voltaic cells (cells that
cannot be recharged) or secondary cells (cells that can be recharged) connected in
series to obtain a desired DC voltage
• A battery stores chemical energy and converts the energy into electrical form
• Aircraft storage batteries are generally rated at 12 or 24 volts
Capacitor - answer• Electrical device used to store charge and energy in the form of an
electrostatic field
• A capacitor is a device made of two parallel conductors separated by an insulator
Conductor - answer• Common building block of electrical circuits that easily permits the
movement of electrons from an electrical source to a load and back to the electrical
source with a minimum of resistance.
• A conductor's resistance depends on such factors as cross sectional area, length,
temperature, and conductor material.
Coulomb - answer• Basic unit of electrical quantity.
• A coulomb is equal to 6.28 billion - billion electrons (6.28 x 10 to the 18th)
Current - answer• The flow of electrons through a conductor is known as current flow.
• The rate of current flow is measured in amperes.
Direct Current (DC) - answer• A flow of electrons in one direction throughout an electric
circuit with constant voltage and current.
• Direct current is caused by a constant difference of potential, both negative and
positive.
Electron - answer• Negatively charged subatomic particles that are located and travel
around (orbit) the nucleus in an imaginary sphere or shell at the speed of light (186,000
miles/second)
• Electrons are involved in the conduction of electricity.
EMF (electromotive force) - answer• The force that causes electrons to flow through a
conductor.
• This force is abbreviated e.m.f.
,• The unit of measurement for eletromotive force is the volt.
• In mathematical problems voltage is expressed by the letter "E".
Farad - answer• Basic unit of capacitance
• One farad holds one coulomb under a pressure of one volt.
Henry (H) - answer• Basic unit of measurement for inductance of an electrical coil
• One (1) henry is the inductance of a coil when a change of current of one (1) ampere
per second induces an e.m.f. of one (1) volt
• In mathematical problems inductance is expressed by the symbol "L".
Inductor - answer• Coil or other device used to introduce inductance into a circuit.
• An inductor is a winding, or coiling, of multiple turns of wire
Insulator - answer• Material or device used to prevent the passage of heat, electricity, or
sound from one medium to another.
Left hand rule - answer• Refers to electrical
• This rule is for determining the direction of movement of a current - carrying conductor
in a magnetic field
Magnetic Permeability - answer• Measure of ease that lines of flux travel through a
material
Magnetism - answer• Ability of a magnet to attract certain materials containing iron and
to influence electrons
• Magnetism is the principle way to effectively produce AC electricity
Metric Prefixes - answer• Measurements relating or using the metric system of
measurement
Neutron - answer• Neutral subatomic particles that exist within the nucleus of all atoms
• Neutrons are not involved in the conduction of electricity
Ohm - answer• Unit of electrical opposition to the flow of current
• A circuit has one ohm of resistance when it limits the flow of current to one amp under
a voltage pressure of one volt
Ohm's Law - answer• Ohm's Law states "the amount of current flowing in a circuit is
directly proportional to the circuit voltage and inversely proportional to the circuit
resistance"
• A plain language statement for Ohm's Law is; One volt causes one ampere to flow
through a resistance of one ohm.
Proton - answer• Positively charged subatomic particles that exist within the nucleus of
all atoms
,• Protons are not involved in the conduction of electricity
Resistance (R) - answer• Electrical characteristic of a conductor
• Opposition that a circuit, component, or substance presents to flow of electricity
• Resistance is the force that opposes or slows down another force, drops voltage, and
consumes power
• Resistance is measured in ohms
• In mathematical problems ohms of resistance is expressed by symbol "R"
Scientific Notation - answer• Short way of expressing a given number between 1 and 10
multiplied by 10 to the appropriate power
Static Electricity - answer• Electrical charge that may be built up on a non-conductive
surface by friction
• Static electricity serves no useful purpose
Volt (V) - answer• Basic unit of electrical pressure
• A volt is the amount of force required to cause one amp of current to flow through one
ohm or resistance
• Volt is often expressed by such terms as voltage, voltage drop, potential difference,
EMF, or IR drop
Watts (W) - answer• Basic unit of power that is the product of voltage multiplied by
current
• One watt is power po
produced in a circuit that has one amp of current flowing under a pressure of one volt
Working Voltage - answer• Maximum amount of DC voltage that can be safely applied
across a capacitor
Alternating Current (AC) - answer• Flow of electrons that continuously changes it value
in magnitude and periodically reverses direction (sine-wave)
• Alternating current is much easier to produce in large quantities as compared to DC.
The time required for one cycle of AC to occur is called the period
Apparently Power - answer• Product of effective voltage and effective current which is
expressed in Volt Amps (VA) rather than Watts (W) without reference to phase shift, if
any, between voltage and current
Capacitive Reactance (XC) - answer• Opposition to current flow in a circuit
• The affect that capacitance has on an AC circuit to lead voltage in phase (ICE)
• Values are given in ohms
Delta Wound - answer• Windings arranged in the shape of a triangle
• For example, on a three-phase generator, motor, or transformer, two of the phase
windings are in series, across the third (phase) winding
, Effective Voltage - answer• Amount of AC that produces the same amount of heat as a
corresponding value of DC
• The effective voltage of AC is referred to as the RMS valve of AC
• Unless otherwise specified, all values of AC are considered effective values
Frequency - answer• Number if cycles of AC completed in one second
• Frequecy is expressed in Hertz (Hz), 1 Hz = 1 cycle of AC/Sound
• The frequency of most AC used in aircraft applications is 400 Hz
Impedanc (Z) - answer• Electrical characteristic of a conductor. Impedance is the total
opposition to the flow of AC in an electrical circuit ( resistance, capacitance, and
inductance)
• Values are given in ohms
Inductive Reactance (XL) - answer• Opposition to current flow in a circuit
• The affect that inductance has on an AC circuit is termed inductive reactance
• Inductance causes current to lag voltage in phase (ELI). Values are given in ohms
Phase Angle - answer• Angle between two similarly varying quantities (sine-waves)
• A phase angle is the difference in angle between two sinusoidally varying quantities
that have the same frequency
Polyphase - answer• Production of two or more phases of AC, or of two or more
alternating voltages of the same frequency
• The most common type of polyphase uses three phases
Power Factor - answer• Ratio of actual power dissipated in an electrical system to the
input power of volts multiplied by amps
• The power factor is the ratio of power dissipated over input
Rectifier - answer• Electronic device that converts AC to DC
• For example, a set of semiconductor diodes connected
Root Mean Square (RMS) - answer• Effective value of sine-wave alternating current
• The RMS value is .707 of the peak value
Sine-Wave - answer• Alternating current wave form produced by a rotary generator
• Sine-waves are values of voltage and current that start at zero and smoothly rise to a
peak value; the waves smoothly fall from a peak back to zero
• The waves then rise to a peak value in a negative direction and smoothly return to
zero
• One AC cycle is produced by 360 degrees of rotation
True Power - answer• Power actually available in an AC circuit
Ampere ( A, amp, amperage) - answer• Unit of measurement used to express the flow
of electrons (electrical current)
• One ampere is a rate of flow of one coulomb (6.28 billion - billion electrons) passing a
given point in an electrical circuit per second
• In mathematical problems amperage is expressed by the letter "I"
Battery - answer• A device consisting of a number of primary voltaic cells (cells that
cannot be recharged) or secondary cells (cells that can be recharged) connected in
series to obtain a desired DC voltage
• A battery stores chemical energy and converts the energy into electrical form
• Aircraft storage batteries are generally rated at 12 or 24 volts
Capacitor - answer• Electrical device used to store charge and energy in the form of an
electrostatic field
• A capacitor is a device made of two parallel conductors separated by an insulator
Conductor - answer• Common building block of electrical circuits that easily permits the
movement of electrons from an electrical source to a load and back to the electrical
source with a minimum of resistance.
• A conductor's resistance depends on such factors as cross sectional area, length,
temperature, and conductor material.
Coulomb - answer• Basic unit of electrical quantity.
• A coulomb is equal to 6.28 billion - billion electrons (6.28 x 10 to the 18th)
Current - answer• The flow of electrons through a conductor is known as current flow.
• The rate of current flow is measured in amperes.
Direct Current (DC) - answer• A flow of electrons in one direction throughout an electric
circuit with constant voltage and current.
• Direct current is caused by a constant difference of potential, both negative and
positive.
Electron - answer• Negatively charged subatomic particles that are located and travel
around (orbit) the nucleus in an imaginary sphere or shell at the speed of light (186,000
miles/second)
• Electrons are involved in the conduction of electricity.
EMF (electromotive force) - answer• The force that causes electrons to flow through a
conductor.
• This force is abbreviated e.m.f.
,• The unit of measurement for eletromotive force is the volt.
• In mathematical problems voltage is expressed by the letter "E".
Farad - answer• Basic unit of capacitance
• One farad holds one coulomb under a pressure of one volt.
Henry (H) - answer• Basic unit of measurement for inductance of an electrical coil
• One (1) henry is the inductance of a coil when a change of current of one (1) ampere
per second induces an e.m.f. of one (1) volt
• In mathematical problems inductance is expressed by the symbol "L".
Inductor - answer• Coil or other device used to introduce inductance into a circuit.
• An inductor is a winding, or coiling, of multiple turns of wire
Insulator - answer• Material or device used to prevent the passage of heat, electricity, or
sound from one medium to another.
Left hand rule - answer• Refers to electrical
• This rule is for determining the direction of movement of a current - carrying conductor
in a magnetic field
Magnetic Permeability - answer• Measure of ease that lines of flux travel through a
material
Magnetism - answer• Ability of a magnet to attract certain materials containing iron and
to influence electrons
• Magnetism is the principle way to effectively produce AC electricity
Metric Prefixes - answer• Measurements relating or using the metric system of
measurement
Neutron - answer• Neutral subatomic particles that exist within the nucleus of all atoms
• Neutrons are not involved in the conduction of electricity
Ohm - answer• Unit of electrical opposition to the flow of current
• A circuit has one ohm of resistance when it limits the flow of current to one amp under
a voltage pressure of one volt
Ohm's Law - answer• Ohm's Law states "the amount of current flowing in a circuit is
directly proportional to the circuit voltage and inversely proportional to the circuit
resistance"
• A plain language statement for Ohm's Law is; One volt causes one ampere to flow
through a resistance of one ohm.
Proton - answer• Positively charged subatomic particles that exist within the nucleus of
all atoms
,• Protons are not involved in the conduction of electricity
Resistance (R) - answer• Electrical characteristic of a conductor
• Opposition that a circuit, component, or substance presents to flow of electricity
• Resistance is the force that opposes or slows down another force, drops voltage, and
consumes power
• Resistance is measured in ohms
• In mathematical problems ohms of resistance is expressed by symbol "R"
Scientific Notation - answer• Short way of expressing a given number between 1 and 10
multiplied by 10 to the appropriate power
Static Electricity - answer• Electrical charge that may be built up on a non-conductive
surface by friction
• Static electricity serves no useful purpose
Volt (V) - answer• Basic unit of electrical pressure
• A volt is the amount of force required to cause one amp of current to flow through one
ohm or resistance
• Volt is often expressed by such terms as voltage, voltage drop, potential difference,
EMF, or IR drop
Watts (W) - answer• Basic unit of power that is the product of voltage multiplied by
current
• One watt is power po
produced in a circuit that has one amp of current flowing under a pressure of one volt
Working Voltage - answer• Maximum amount of DC voltage that can be safely applied
across a capacitor
Alternating Current (AC) - answer• Flow of electrons that continuously changes it value
in magnitude and periodically reverses direction (sine-wave)
• Alternating current is much easier to produce in large quantities as compared to DC.
The time required for one cycle of AC to occur is called the period
Apparently Power - answer• Product of effective voltage and effective current which is
expressed in Volt Amps (VA) rather than Watts (W) without reference to phase shift, if
any, between voltage and current
Capacitive Reactance (XC) - answer• Opposition to current flow in a circuit
• The affect that capacitance has on an AC circuit to lead voltage in phase (ICE)
• Values are given in ohms
Delta Wound - answer• Windings arranged in the shape of a triangle
• For example, on a three-phase generator, motor, or transformer, two of the phase
windings are in series, across the third (phase) winding
, Effective Voltage - answer• Amount of AC that produces the same amount of heat as a
corresponding value of DC
• The effective voltage of AC is referred to as the RMS valve of AC
• Unless otherwise specified, all values of AC are considered effective values
Frequency - answer• Number if cycles of AC completed in one second
• Frequecy is expressed in Hertz (Hz), 1 Hz = 1 cycle of AC/Sound
• The frequency of most AC used in aircraft applications is 400 Hz
Impedanc (Z) - answer• Electrical characteristic of a conductor. Impedance is the total
opposition to the flow of AC in an electrical circuit ( resistance, capacitance, and
inductance)
• Values are given in ohms
Inductive Reactance (XL) - answer• Opposition to current flow in a circuit
• The affect that inductance has on an AC circuit is termed inductive reactance
• Inductance causes current to lag voltage in phase (ELI). Values are given in ohms
Phase Angle - answer• Angle between two similarly varying quantities (sine-waves)
• A phase angle is the difference in angle between two sinusoidally varying quantities
that have the same frequency
Polyphase - answer• Production of two or more phases of AC, or of two or more
alternating voltages of the same frequency
• The most common type of polyphase uses three phases
Power Factor - answer• Ratio of actual power dissipated in an electrical system to the
input power of volts multiplied by amps
• The power factor is the ratio of power dissipated over input
Rectifier - answer• Electronic device that converts AC to DC
• For example, a set of semiconductor diodes connected
Root Mean Square (RMS) - answer• Effective value of sine-wave alternating current
• The RMS value is .707 of the peak value
Sine-Wave - answer• Alternating current wave form produced by a rotary generator
• Sine-waves are values of voltage and current that start at zero and smoothly rise to a
peak value; the waves smoothly fall from a peak back to zero
• The waves then rise to a peak value in a negative direction and smoothly return to
zero
• One AC cycle is produced by 360 degrees of rotation
True Power - answer• Power actually available in an AC circuit
