Basic Electricity Flashcards

1
Q

One kilowatt is equal to how many watts?

A

1000 watts

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2
Q

What law describes the most fundamental or basic relationships in an electrical circuit?

A

Ohm’s law.

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3
Q

What are the three elements of Ohm’s law?

A

Voltage, current and resistance.

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4
Q

How would you write Ohm’s law as an equation?

A

E = I x R, R = E/I, I = E/R.

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5
Q

If the resistance in a DC circuit remains the same but the voltage doubles, what happens to the amount of current flowing in a circuit?

A

It also doubles.

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6
Q

In DC circuits, what unit measures power?

A

Watts.

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7
Q

What three elements are required to form an electrical circuit?

A

A source of electrical energy, a load or resistance to use the electricity, and wires or conductors to connect the source to the load.

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8
Q

DC circuits can take one of three forms or types. What are they?

A

Series, parallel, and complex ( or series-parallel ).

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9
Q

A 24-volt lead-acid battery has how many cells?

A

Twelve.

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10
Q

A fully charged lead-acid battery has a specific gravity that varies between what two values?

A

1.275 and 1.300

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11
Q

You must apply a correction to the specific gravity reading of the electrolyte of a lead-acid battery when the temperature is outside of what two values?

A

Whenever the temperature is less than 70 degrees Fahrenheit or more than 90 degrees Fahrenheit.

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12
Q

What is the reason for having separate facilities for storing and serving nickel-cadmium and lead-acid batteries?

A

The electrolyte in the two types of batteries is chemically opposite and the fumes from one type can contaminate the electrolyte of the other type.

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13
Q

The state of charge of a nickel-cadmium battery cannot be determined by measuring the specific gravity of the electrolyte for what reason?

A

There is no significant change in the specific gravity of the electrolyte as the battery is charged or discharged.

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14
Q

What is the principal advantage of AC current over DC current?

A

Power can be transmitted over long distances more efficiently and with smaller wires because the voltage can be easily increased or decreased by a transformer.

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15
Q

What are the three causes of opposition to current flow in an AC circuit?

A

Resistance, inductive reactance, and capacitive reactance.

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16
Q

Define inductance.

A

An induced voltage which is opposite in direction to the applied voltage.

17
Q

What component creates capacitance in AC circuits?

A

A capacitor.

18
Q

How does a capacitor store electricity?

A

The energy is stored in the form of an electrostatic charge or field that exists between two conductors separated by an insulator.

19
Q

What property of an AC circuit is defined by the term “impedance”?

A

The total opposition to current flow.

20
Q

What are two reasons that might cause a nickel-cadmium battery to fail to deliver its rated capacity?

A

Faulty cells or cell imbalance.

21
Q

What electrical values are measured by a typical multimeter?

A

Voltage, current, and resistance.

22
Q

What is a common cause of damage to solid-state components and/or integrated circuits?

A

Electro-static discharge from the human body during handling.

23
Q

Describe magnetism.

A

An object’s properties which attract metallic substances.

24
Q

When the external magnetizing force is removed, the difference between permanent and temporary is?

A

Permanent magnets retain their magnetism. Temporary magnets rapidly lose magnetism.

25
Q

What change occurs in a D.C. circuit when applied voltage is increased and resistance remains constant?

A

Current increases.

26
Q

What are common methods electrical energy can be produced?

A

Combination circuit and series-parallel.

27
Q

Compare AC & DC circuits in aircraft.

A

DC flows constantly in one direction. AC has the ability to change direction at or during regular intervals and lighter in weight.

28
Q

How much voltage do most aircraft require for special equipment?

A

Most 24-volt aircraft systems need 400 cycle AC current.

29
Q

The function of a capacitor in an AC circuit is…

A

To store electrical energy.

30
Q

How is inductance represented in an AC circuit?

A

By a coil.

31
Q

What is a common use of most multimeters?

A

Troubleshooting and reading measurements for voltage, resistance, current ,continuity, capacitance, and inductance.

32
Q

Define short circuit.

A

Low resistance path between a component and/or a conductor and ground.

33
Q

Using a multimeter, how would a technician read current?

A

Inserting the ammeter or multimeter in series by opening or breaking the circuit.

34
Q

What is considered to be the open-circuit voltage of a fully charged 12 cell lead-acid battery?

A

Approximately 26.4 volts or ( 12 x 2.2 volts) 28 volts are required for charging.

35
Q

What is the open-circuit cell voltage of a Ni-Cad battery?

A

1.25 volts.

36
Q

Can Ni-Cad batteries be interchangeable with Lead-Acid types?

A

Yes.

37
Q

What should be done when interchanging a Ni-Cad Battery with a Lead-Acid battery?

A

Clean, dried, and neutralized with boric acid or ammonia, then completely air/oven dry.