Basic Electricity study guide questions

The working voltage of a capacitor in an AC circuit should be

50% greater

The term that describes the combined resistive forces in an AC circuit is

impedance

What is the opposition to the flow of AC produced by an EMF with generated back voltage called?

Inductive reactance

Electrostatic fields are also known as

Dielectric fields

The basis for transformer operation in the use of AC is mutual

Inductance

The opposition offered by a coil to the flow of AC (ignoring resistance) is called

Inductive reactance

What factors strengthen a coil inductor

Adding coils close together

An increase in which of the following factors will cause an increase in the inductive reactance of a circuit

Inductance and frequency

When different rated capacitors are connected in series in a circuit, the total capacitance is

1/1/c1 + 1/c2 + 1/c3 …

Less than the capacitance of the lowest rated capacitor

Capacitors are sometimes used in DC circuits to

Smooth out slight pulsations in current/voltage

In an AC circuit, the effective voltage is

Greater than the maximum instantaneous voltage

The amount of electricity a capacitor can store is directly proportional to the

Plate area and inversely proportional to the distance between the plates

.02 + .05 + .10 microfarad

1/ 1/c1 + 1/c2 + 1/c3

.0125 microfarads

.02 + .05 + .10 microfarad

C1 + c2 + c3

.170 microfarads

Convert farads to microfarads by

Multiplying farads by 10^6

Convert farads to picofarads by

Multiplying farads by 10^12

Any values given for current or voltage in an AC circuit are assumed to be

effective values

When different rated capacitors are connected in parallel in a circuit, total capacitance is

C1 + c2 + c3

Equal to the sum of all the capacitances

When inductors are connected in series in a circuit, total inductance is

Equal to the sum of the individual inductances

When more than two inductors of different inductances are connected in parallel in a circuit, total inductance is

1/ 1/l1 + 1/l2 + 1/l3

Less than the inductance of the lowest rated inductor

.03 + .12 + .25 microfarads

C1 + c2 + c3

.4 microfarads

What requires the most electrical power during operation

Two light requiring 4 amps each in a 24 volt parallel system

How much power must a 24 volt generator furnish to a system which contains the following loads

One motor (75% efficient)

Three position lights

One heating element

One anticollison light

450 watts

A 12 volt electric motor has 1000 watts and 1 horsepower output. Maintaining the same efficiency, how much input power will a 24 volt, 1 horse power electric motor require

1000 watts

How many amperes will a 28 volt generator be required to supply to a circuit containing five lamps in parallel, three of which have a resistance of 6 ohms each and two of which have a resistance of 5 ohms each

25.23 amps

24 volt, 1hp DC electric motor that is 80% effienct requires 932.5 watts. How much power will a 12 volt, 1hp DV electric motor that is 75% efficient

994.6 watts

Potential difference measured in what

Volts

Which energy does not apply to the movement of electrons flowing in a conductor

Static energy

24 volt source is required to furnish 48 watts to a parallel circuit consisting of 4 resistors of equal value. Voltage drop for each resistor is?

24 volts

When calculating power in a reactive or inductive AC circuit, the true power is

Less than the apparent power

How much power is being furnished to the circuit (fig 4)

2.645 watts

Impedance of an AC series circuit consisting of an inductor with a reactance of 10 ohms, a capacitor with a reactance of 4 ohms, and a resistor with a resistance of 8 ohms

10 ohms

If r5 is disconnected at the junction of r4 and r3 as shown, what will the ohmmeter read

(Fig 6)

3 ohms

If r3 is disconnected at terminal D, what will the ohmmeter read (fig 7)

Infinite Résistance

With an ohmmeter connected into the circuit as shown, what will the ohmmeter read? (Fig 8)

10 ohms

How many Instruments (voltmeters and ammeters) are installed correctly (fig 9)

Two

Correct way to connect a test voltmeter in circuit is

In parallel with a Unit

What will a voltmeter read if properly connected across a closed switch in a circuit with electrical power on

Zero voltage

What does the letter Q symbolize when measuring electrical charge

Coulomb

.001 ampere

Milliampere

A cabin entry light of 10 watts and a dome light of 20 watts are connected in parallel to a 39 volt source. If the voltage across the 10 watt light is measured, it will be

Equal to the voltage across the 20 watt light

14 ohm resistor is to be installed in a series circuit carrying a 0.5 ampere. How much power will the resistor be required to dissipate

At least 35 milliwatt

.002 kV equals

2.0 volts

What is the measured voltage of the series parallel circuit between terminal a and b (fig 10)

3.0 volts

24 volt source is required to furnish 48 watts to a parallel circuit consisting of two resistors of each value. What is the value is each resistor

24 ohms

Which requires the most electrical power

1/5 hp, 24 volt motor which is 75% efficient

What unit is used to express electrical power

Watts

Basic unit of electrical quantity

Coulomb

What is the operating resistance of a 30 watt light bulb designed for a 28 volt system

26 ohms

When referring resistance in a parallel DC circuit, which of the following statements is true

The total current is equal to the sum of the currents through the individual branches of the circuit

Which one of the following is commonly used as a rectifier in electrical circuits

Diodes

Diodes are used in electrical power supply circuits primarily as

Rectifiers

Transfer of electric energy from one circuit to another without the aid of electrical connections

Is called induction

If 3 resistors of 3 ohms, 5 ohms, and 22 ohms are connected in series in a 28 volt circuit, how much current will flow through the 3 ohm resistor

0.93 amps

A circuit has an applied voltage of 30 volts and a load consisting of a 10 ohm resistor in series with a 20 ohm resistor. What is the voltage drop across the 10 ohm resistor

10 volts

Find the total current flowing in the wire between points c and d (fig 11)

3.0 amps

Find the voltage across the 8 ohm resistor (fig 11)

24 volts

In a parallel circuit with a four 6 ohm resistors across a 24 volt battery, what is the total voltage across resistor 3 in the circuit

24 volts

If each cell, connected in series, equal 2 volts, how would a 12 cell lead acid battery be rated

24 volts

Find the total resistance of the circuit (fig 12)

21.2 ohms

Which is correct in Ref to electrical resistance

If one of the three bulbs in a parallel lighting circuit is removed, the total resistance of the circuit will become greater

What happened to the current in a voltage step up transformer with a ratio of 1 to 4

The current stepped down by a 1 to 4 ratio

Determine the total current flow in the circuit

1.4 amps

In a parallel circuit with three 6 ohm resistors across a 12 volt battery, what is the total current value in the circuit

6 amps

Total resistance of the circuit is (fig 14)

17 ohms

Which of these will cause the resistance of a conductor to decrease?

Decrease the length or increase the cross sectional area

Through which material will magnetic lines of form pass the most readily?

Iron

(Refer to Figure 64.) A 48-volt source is require to furnish 192 watts to a parallel circuit consisting a three resistors of equal value. What is the value of each resistor?

36 ohms

Which is correct concerning a parallel circuit?

Total resistance will be smaller than the smallest resistor

The voltage drop in a circuit of known resistance is dependent on

The amperage of the circuit

A thermal switch, or thermal protector, as used in an electric motor, is designed to

Open the circuit in order to allow cooling of the motor

(Refer to Figure 15.) With the landing gear retracted, the red indicator light will not come on if an open occurs

19

(Refer to Figure 15.) Wire 7 is used to

Close the PUSH TO TEST circuit

(Refer to Figure 15.) When the landing gear is down, the green light will not come on if an open occurs in wire

6

(Refer to Figure 16.) What will be the effect if the PCO relay fails to operate when the left-hand tank is selected?

The fuel pressure cross feed valve open light will not illuminate

Refer to Figur 16 the bus and they mill operate it 24-volts DC is applied to the bus and the fuel tank selector is in the

Cross feed position

(Refer to Figure 16.) With power to the bus and the fuel selector switched to the right-hand tank, how many relays in the system are operating?

Three

(Refer to Figure 16) When electrical power is applied to the bus, which relays are energized?

PCC AND TCC

(Refer to Figure 16) When electrical power is applied to the bus, which relays are energized?

5 6 11 12 13 15 16

(Refer to Figure 19. Under which condition will a ground be provided for the warning horn through both gear switches when the throttles are closed?

Left gear up and right gear down

(Refer to Figure 19) When the throttles are retarded with only the right gear down, the warning horn will not sound if an open occurs in wire

5

(Refer to Figure 19.) When the landing gears are up and the throttles are retarded, the warning horn will not sound if an open occurs in wire

6

When referring to an electrical circuit diagram, what point is considered to be at zero voltage?

The ground ref

What is the purpose of the ground symbol used in electrical circuit diagrams?

To show that there is a return path for the current between the source and the load

(Refer to Figure 20. Troubleshooting an open circuit with a voltmeter as shown in this circuit will

Permit the battery voltage to appear on the voltmeter

(Refer to Figure 21) Which symbol represents a variable resistor?

2

In a P-N-P transistor application, the solid-state device is turned on when the

Base is negative with respect to the emitter

In an N-P-N transistor application, the solid-stat device is turned on when the

Base is positive with respect to the emitter

Typical application for zener diodes is as

Voltage regulator

(Refer to Figure 22.) Which illustration is correct concerning bias application and current (positive charge) flow?

1

Forward biasing of a solid-state device will cause the device to

Conduct

(Refer to Figure 23.) If an open occurs at R1, the light

Cannot be turned off

(Refer to Figure 23.) If R2 sticks in the up position, the light will

Be on Full bright

(Refer to Figure 24.) Which statement concerning the depicted logic gate is true?

Any input being 1 will produce to 1 output

(Refer to Figure 25) In a functional and operating circuit, the depicted logic gate's output will be 0

When one or more inputs are 0

(Refer to Figure 26.) Which of the logic gate output conditions is correct with respect to the given inputs?

2

Which of the following logic gates will provide an active high out only when all inputs are different?

XOR

A lead-acid battery with 12 cells connected in series (no-load voltage = 2.1 volts per cell) furnishes 10 amperes to a load of 2-ohms resistance. The internal resistance of the battery in this instance is

0.52 ohm

If electrolyte from a lead-acid battery is spilled in the battery compartment, which procedure should be followed?

Apply sodium bicarbonate solution to the affected area followed by a water rinse

Which statement regarding the hydrometer reading of a lead acid storage battery electrolyte is true?

The hydrometer reading does not require a temperature correction if the electrolyte temperature is 80F