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complete solution
Electricity
The physical phenomena arising from the existence and interaction of an electrical
charge
Voltage / Electromotive Force (EMF)
The amount of force being applied to a circuit to produce an electron flow
Amperage / Current Flow
The quantity of electricity flowing through the circuit
Resistance
The opposition to the flow of electrons offered by a device or material
Ohms
The measurement of resistance to current flow
Watt
The measurement of electrical work done
Forms of Electricity
Static and Dynamic
Static Electricity
(1) Electricity at rest
(2) Begins with a build up of either a positive or negative electron charge. If two
negative charges or two positive charges are brought close together, the objects that
hold that charge repel each other. If a positive charge is brought within close proximity
of a negative charge, the two objects attract each other
(3) Static electricity is produced by friction and is not easily measured nor is it
controllable or usable
Dynamic Electricity
A practical form of current flow that is used in everyday life. This form of electricity is
easily produced, measured, and controlled
Methods of Producing Dynamic Electricity
Mechanical, Chemical, Thermal, and Pressure
Mechanical
Produced by rotating a magnetic field through another magnetic field
Ex: A Grass Cutter
Chemical
Produced by surrounding two or metallic plates with a chemical electrolyte
Ex: A Battery
Thermal
Produced by joining two dissimilar metals and applying heat
Ex: Thermocouple
, Pressure
Produced by applying pressure to quartz, which will produce an electron flow
Ex: A Watch
Types of Electricity
AC and DC
Direct Current (DC)
Current that is a steady flow in one direction only. It is produced mechanically by a DC
generator, or chemically by a battery
Ex: A Flashlight
Alternating Current (AC)
Current flow that reverses direction at specific intervals, defined as Hertz / Cycles. It is
produced mechanically by an AC generator
Ex: A TV Screen
Electrical Test Equipment
Multimeter
Multimeter Test Leads
Red lead = Positive and Black lead = Negative
Multimeter Digital Display Features
Power Up, Overload Indication (OL), and Low Battery Indicator
Power Up
All segments appear while the instrument performs a self-test. At the end of the test,
meter will chirp once indicating that it is ready for use
Overload Indication (OL)
Indicates input is too large to display
Low Battery Indicator
Appears when approximately 100 hours of life remain. If left on, the meter will go to
standby mode after one hour to save the battery
Systems / Components of the Engine Electrical System
Engine Speed Indicating System, Engine Temperature Indicating System, Fuel Flow
Indicating System, Oil Pressure Indicating System and Engine Fire Detection System
Engine Speed Indicating System's Components
Tachometer (RPM) Indicator and Tachometer Generator
Tachometer (RPM) Indicator
Indicates engine compressor rotor RPM in percent. It is located in the flight station /
cockpit
Tachometer generator
(1) Mounted and splined to the accessory gearbox
(2) Creates an electrical reference signal that represents the rotational speed of the
engine compressor
(3) The reference signal is transmitted to the tachometer (RPM) indicator and is read as
percent of compressor RPM
complete solution
Electricity
The physical phenomena arising from the existence and interaction of an electrical
charge
Voltage / Electromotive Force (EMF)
The amount of force being applied to a circuit to produce an electron flow
Amperage / Current Flow
The quantity of electricity flowing through the circuit
Resistance
The opposition to the flow of electrons offered by a device or material
Ohms
The measurement of resistance to current flow
Watt
The measurement of electrical work done
Forms of Electricity
Static and Dynamic
Static Electricity
(1) Electricity at rest
(2) Begins with a build up of either a positive or negative electron charge. If two
negative charges or two positive charges are brought close together, the objects that
hold that charge repel each other. If a positive charge is brought within close proximity
of a negative charge, the two objects attract each other
(3) Static electricity is produced by friction and is not easily measured nor is it
controllable or usable
Dynamic Electricity
A practical form of current flow that is used in everyday life. This form of electricity is
easily produced, measured, and controlled
Methods of Producing Dynamic Electricity
Mechanical, Chemical, Thermal, and Pressure
Mechanical
Produced by rotating a magnetic field through another magnetic field
Ex: A Grass Cutter
Chemical
Produced by surrounding two or metallic plates with a chemical electrolyte
Ex: A Battery
Thermal
Produced by joining two dissimilar metals and applying heat
Ex: Thermocouple
, Pressure
Produced by applying pressure to quartz, which will produce an electron flow
Ex: A Watch
Types of Electricity
AC and DC
Direct Current (DC)
Current that is a steady flow in one direction only. It is produced mechanically by a DC
generator, or chemically by a battery
Ex: A Flashlight
Alternating Current (AC)
Current flow that reverses direction at specific intervals, defined as Hertz / Cycles. It is
produced mechanically by an AC generator
Ex: A TV Screen
Electrical Test Equipment
Multimeter
Multimeter Test Leads
Red lead = Positive and Black lead = Negative
Multimeter Digital Display Features
Power Up, Overload Indication (OL), and Low Battery Indicator
Power Up
All segments appear while the instrument performs a self-test. At the end of the test,
meter will chirp once indicating that it is ready for use
Overload Indication (OL)
Indicates input is too large to display
Low Battery Indicator
Appears when approximately 100 hours of life remain. If left on, the meter will go to
standby mode after one hour to save the battery
Systems / Components of the Engine Electrical System
Engine Speed Indicating System, Engine Temperature Indicating System, Fuel Flow
Indicating System, Oil Pressure Indicating System and Engine Fire Detection System
Engine Speed Indicating System's Components
Tachometer (RPM) Indicator and Tachometer Generator
Tachometer (RPM) Indicator
Indicates engine compressor rotor RPM in percent. It is located in the flight station /
cockpit
Tachometer generator
(1) Mounted and splined to the accessory gearbox
(2) Creates an electrical reference signal that represents the rotational speed of the
engine compressor
(3) The reference signal is transmitted to the tachometer (RPM) indicator and is read as
percent of compressor RPM
