Basic Electricity Flashcards
What is inductance?
Induced voltage which is opposite in direction to the applied voltage.
What is the function of a capacitor?
Serves as a reservoir or storehouse for electricity
What causes opposition to the flow of applied current in an A.C. circuit?
Inductive reactance and capacitance reactance.
What represents capacitance in A.C. circuits?
A capacitor
What does an electrical circuit consist of?
A source of electrical pressure, resistance in the form of an energy consuming device, and conductors in the forms of wires to provide electron flow.
Why should nickel-cadmium batteries and lead-acid batteries not be stored or serviced in the same area?
The electrolyte in ni-cad batteries is chemically opposite to the lead-acid battery electrolyte and the fumes from lead-acid batteries can contaminate the electrolyte in ni-cad batteries.
What is the most important law applicable to the study of electricity?
Ohm’s law
What are the elements of ohm’s law?
Voltage, current, and resistance
What unit is used to measure power in D.C. circuits?
Watt
How many watts are equal to one kilowatt?
1,000 watts
What are three types of DC electrical circuits?
Series, parallel, and series pallel
What current changes occur in a DC circuit when the applied voltage is increased and the resistance remains constant?
The current increases.
What are the functions of most multimeters?
The can indicate amperes, volts and ohms.
What could cause a ni-cad battery to fail to deliver its rated capacity?
cell imbalance or faulty cells
What is one advantage of AC circuits over DC circuits in aircrafts?
1) AC can be transmitted over long distances more readily and more economically than DC.
2) Space and weight can be saved.
3) Circuit breakers will operate satisfactorily at altitude.
4) AC devices are smaller and simpler
5) Most 24 volt aircraft systems have special equipment that require certain amounts of 400 cycle AC current.
What should be the specific gravity of the electrolyte in a fully charged lead-acid battery?
Specific gravity should be between 1.275 and 1.300
Define the term “Impedence”
The total opposition to the flow of current in an electrical system.
How many cells make up a lead-acid battery rated at 24 volts?
12 cells
Why is a specific gravity check of the electrolyte in a ni-cad battery not acceptable to determine battery charge?
The electrolyte specific gravity does not change with the state of charge.
What is the effect of temperature on specific gravity of the electrolyte when checking a lead acid battery?
Battery temperature changes electrolyte density only when greater than 90 degrees F or less than 70 degrees F.
What is the difference between permanent and temporary magnets?
When an external magnetizing force is removed, permanent magnets retain their magnetism for an extended time whereas temporary magnets quickly lose most of their magnetism.
How is Ohm’s law expressed as an equation?
I=E/R ;
R=E/I;
E=IxR
What is the most frequent cause of damage to solid state components and integrated circuits?
Electro-static discharge from the human body due to careless handling
How would a technician connect a meter in a circuit to read its current?
Insert the meter in series by opening or breaking the circuit.
What is magnetism?
The property of an object to attract certain metallic substances
What is the definition of a short circuit?
An unintentional low resistance path between a component/ conductor and ground.
What is the name of the concept that describes the relationship between electricity and magnetism?
Electromagnetism
What is the common name for the lines of force that make up a field surrounding a magnet?
Magnetic flux or flux lines
Name at least two sources of electrical energy
Thermal, light, pressure, and chemical
What is the general purpose of a resistor?
To limit the amount of current flow
How may a small fixed resistor’s value be easily determined?
By the color bands on the surface of the resistor
What is the basic unit of measure of capacitance?
Farad
Name at least 2 types of resistors
Fixed, variable, rheostat, potentiometer, thermistor
What is the standard unit of measure of frequency?
Hertz
Describe a basic capacitor
Two parallel plates separated by a dielectric
What component can change the electrical energy of a voltage to a different level of energy?
Transformer
What is the basic unit of the measure of inductance?
Henry
When using a multi-meter, what setting , or type of check, is typically used to determine an open in a conductor?
Continuity
When troubleshooting for open circuits with a multi-meter, a closed circuit, or a good wire, will be indicated with what reading?
A near zero reading
What instrument is used to measure the density of the electrolyte in a Lead Acid battery?
Hydrometer
Name the two types of battery commonly used in modern aircraft.
Lead acid and nickel cadmium
In regards to batteries, what is an SLA battery
Sealed Lead Acid battery
What component can change a DC current into AC current?
An Inverter
What component can transform AC into DC?
A rectifier
What is the basic component that allows current to flow in one direction only?
A diode
What does the acronym LED stand for?
Light Emitting Diode
Describe a basic OR gate.
A standard logic symbol that has two or more inputs and only one output. Only one input signal has to be received (true) in order for there to be an output signal transmitted.
Describe a basic AND gate
A standard logic symbol that has two inputs or more and one output. The two input signals MUST be received (true) in order for there to be an output signal transmitted.
