Delmar 7

A capacitor is connected to a 240V supply. An ammeter indicates 3 A. What is the capacitive reactance of the capacitor? 23 Ω 30 Ω 71 Ω 80 Ω

80 Ω

What is the symbol for capacitive reactance? C XC L XL

XC

Two capacitors, a 20 μF and a 30 μF, are connected in parallel. What is the total capacitance? 12 μF 50 μF

50 μF

Two capacitors, a 20 μF and a 30 μF, are connected in parallel to a 60-Hz source. What is the total capacitive reactance? 7.96 Ω 23.16 Ω 42.04 Ω 53.05 Ω

53.05 Ω

What is the reactance of a 10 pF capacitor when the applied frequency is 30-Hz? 200.36 Ω 325.76 Ω 530.52 Ω 612.83 Ω

530.52 Ω

In an RC parallel circuit, ET = 240 V, R = 1000 Ω, and XC = 1500 Ω. What is the apparent power? 38.4 VA 57.6 VA 56 VA 69.23 VA

69.23 VA

Two capacitors, a 20 μF and a 30 μF, are connected in parallel to a 400-Hz source. What is the total capacitive reactance? 7.96 Ω 33.16 Ω 42.04 Ω 53.05 Ω

7.96 Ω

In a series RC circuit, apparent power can be calculated by _____. ET × I ER × I EC × I

ET × I

The procedure for solving a resistive-capacitive series circuit is the exact same as for solving for a resistive-inductive series circuit. True False

F

As the resistor is charged, an impressed voltage is developed across its plates as an electrostatic charge is built up. True False

False

The power factor is the sine of angle theta. True False

False

With the JAN standard of capacitor markings, the fourth dot indicates classes A to E of temperature and leakage coefficients. True False

False

In a series RC circuit, total impedance is a combination of resistance and capacitive reactance. True False

True

Temperature coefficients are listed in parts per million per degree Celsius. True False

True

The countervoltage in a capacitive reactance is similar to the countervoltage produced by an inductor True False

True

The dielectric test set contains a variable voltage control, a voltmeter, and a microammeter. True False

True

The power factor is the ratio of true power to apparent power. True False

True

The power required to charge the capacitor in a pure capacitive circuit is returned to the circuit when the capacitor discharges. True False

True

When a capacitor is connected to an AC circuit, current appears to flow through the capacitor. True False

True

The power in a capacitor is reactive power. What is the unit for reactive power? W VA P VAR

VAR

Which of these formulas would be used to calculate reactive power?

VARs=Ec*I

By how many degrees is the voltage and current out of phase with each other when a circuit of both resistance and capacitance is connected to an AC circuit? between 0° and 30° between 45° and 90° between 0° and 90° between 90° and 180°

between 0° and 90°

In a pure capacitive circuit, the current _____ the applied voltage by _____. leads; 180° lags; 180° leads; 90° lags; 90°

leads; 90°

Polarized capacitors _____. must be used with AC only must be used with DC only can be used with either AC or DC

must be used with DC only

A temperature coefficient that is __________ indicates the capacitor will decrease its capacitance with a decrease in temperature. negative positive neutral stable

negative

When the voltage and current have _____ polarities in a pure capacitive circuit, the capacitor is discharging and the energy is returned to the circuit. the same opposite

opposite

In what unit is the capacitance value given for a dipped tantalum capacitor? watts farads picofarads temperature coefficient

picofarads

When resistance and capacitive reactance are 90° degrees out of phase with each other, they form a right triangle. What is the impedance? the hypotenuse the vector angle the cosine the adjacent side

the hypotenuse

Two capacitors, a 20 μF and a 30 μF, are connected in series. What is the total capacitance? 12 μF 50 μF

12 μF

The quality of a capacitor is generally very low. True False

False

Color bands and dots on a dipped tantalum capacitor determine the value, tolerance, and voltage. True False

True

Power factor can be calculated by dividing any resistive value by its like total value. True False

True

Reactive power in a circuit can be calculated in a manner similar to that used for watts except that reactive values of voltage and current are used instead of resistive values. True False

True

Resistive-capacitive series circuits are similar to resistive-inductive series circuits. True False

True

The apparent power, true power, and reactive power form a right triangle in an RC parallel circuit. True False

True

When a circuit containing both resistance and capacitance is connected to an AC circuit, the voltage and current could be out of phase with each other at 63°. True False

True

What is the unit for capacitive reactance? ohm mica henry coulomb

ohm

What does ER represent? total energy total circuit impedance voltage drop across the capacitor voltage drop across the resistor

voltage drop across the resistor

How are small electrolytic capacitors generally tested for shorts? with an ohmmeter with a variable DC power supply with a microammeter with a HIPOT

with an ohmmeter

In a series RC circuit, ET = 240 V, R = 40 Ω, and XC = 30 Ω. What is EC? 37.14 V 62.86 V 92 V 144 V

144 V

A series RC circuit contains two resistors and two capacitors. The resistors are 82 Ω and 47 Ω. The capacitors have capacitive reactances of 80 Ω and 50 Ω. What is the total impedance? 14.56 Ω 68.62 Ω 84.75 Ω 183.14 Ω

183.14 Ω

In an RC parallel circuit, ET = 277 V, R = 82 kΩ, and XC = 33 kΩ. What is the apparent power? .33 VA 2.51 VA 2.93 VA 3.26 VA

2.51 VA

o capacitors, a 20 μF and a 30 μF, are connected in series to a 400-Hz source. What is the total capacitive reactance? 7.96 Ω 33.16 Ω 42.04 Ω 53.05 Ω

33.16 Ω

In an RC parallel circuit, ET = 480 V, R = 50 kΩ, and XC = 47 kΩ. What is the reactive power? 4.90 VARs 5.36 VARs 6.38 VARs 7.61 VARs

4.90 VARs

Three capacitors, a 12 μF, a 20 μF and a 30 μF, are connected in series. What is the total capacitance? 6 μF 62 μF

6 μF

Three capacitors, a 12 μF, a 20 μF and a 30 μF, are connected in parallel. What is the total capacitance? 6 μF 62 μF

62 μF

Three capacitors, a 12 μF, a 20 μF, and a 30 μF, are connected in series to a 400-Hz source. What is the total XC? 36.42 Ω 42.78 Ω 52.09 Ω 66.32 Ω

66.32 Ω

When a circuit containing both resistance and capacitance is connected to a ______, the voltage and current will be out of phase with each other. AC circuit DC circuit series circuit parallel circuit

AC circuit

When a capacitor is connected to an AC circuit, the __________ charges one plate of the capacitor positive and the other plate negative. DC generator AC generator capacitor reactor

AC generator

Another type of polarized capacitor is the trimmer capacitor. True False

False

EC represents capacitive reactance. True False

False

In an RC parallel circuit, voltage across all branches do not need to be the same. True False

False

Capacitors are used extensively in electronic circuits for control of frequency and pulse generation. True False

True

The total impedance is the total current-limiting element in the circuit. True False

True

When the power factor and apparent power are known, the true power can be calculated for an RC parallel circuit. True False

True

When the total impedance of the circuit is known, the total current flow can be calculated. True False

True

Of the different power values in an RC circuit, which is known as apparent power? VA W VARs

VA

The capacitive reactance of a capacitor is _____ proportional to frequency. directly inversely

inversely

In some capacitors, there is a small amount of current that flows from one plate, through the dielectric material to the other plate. This current is called _____ current. leakage conduction electrostatic electrolytic

leakage

The _____ of a circuit is the cosine of the phase angle. watts power factor VARs volt-amperes

power factor

In the quality of a capacitor formula, what is represented by VARs? reactive power apparent power true power applied power

reactive power

The voltage rating of a capacitor _____. can be exceeded as long as the time is under one hour should never be exceeded is only a suggested maximum is a minimum working voltage

should never be exceeded

On a ceramic capacitor, what does the wide band indicate? temperature coefficient multiplier tolerance second digit

temperature coefficient

In an RC parallel circuit, how is circuit power factor determined? the ratio of resistance and capacitance the ratio of resistance and current the ratio of resistance and true power the ratio of true power and capacitance

the ratio of resistance and capacitance

ER represents voltage drop across the resistor. True False

False

There is true power produced in a pure capacitive circuit. True False

False

Counter voltage presented by a capacitor is called _____. capacitance inductance capacitive reactance inductive reactance

capacitive reactance

Dividing a circuit's total applied voltage by the total impedance results in the total _____. current power VA VARs

current

When calculating an RC parallel circuit value, what does IR represent? capacitance of the capacitor current flow through the capacitor total circuit current current flow through the resistor

current flow through the resistor

A charge curve for a capacitor is divided into _____ time constants. two three four five

five

In an RC parallel circuit, the voltage across the resistor and the voltage across the capacitor are _____. less than 90° out of phase with the resistor voltage lagging in phase less than 90° out of phase with the resistor voltage leading 180° out of phase

in phase

A capacitor is constructed by separating two metal conductors known as _____ with an insulating material known as a(n) _____. plates; dielectric dielectrics; plate electrolytes; ceramic ceramics; electrolyte

plates; dielectric

In the formula Q = C x V, what does Q stand for? capacitance in farads charge in coulombs charging voltage capacitance in picofarads

capacitance in farads

Three capacitors, a 12 μF, a 20 μF, and a 30 μF, are connected in parallel to a 60-Hz source. What is the total XC? 6.42 Ω 42.78 Ω 442.09 Ω 566.32 Ω

442.09 Ω

Three capacitors, a 12 μF, a 20 μF, and a 30 μF, are connected in series to a 60-Hz source. What is the total XC? 226.42 Ω 342.78 Ω 442.09 Ω 566.32 Ω

442.09 Ω

In an RC parallel circuit, ET = 120 V, R = 47 kΩ, and XC = 27 kΩ. What is IT? 4.62 mA 5.13 mA 6.44 mA 7.55 mA

5.13 mA

A series RC circuit contains two resistors and two capacitors. The resistors are 68 Ω and 56 Ω. The capacitors have capacitive reactances of 66 Ω and 33 Ω. The applied voltage is 240 V. What is the voltage drop on the 56 Ω resistor? 39.83 V 49.91 V 84.70 V 102.85 V

84.70 V

In an RC parallel circuit, the supply voltage is 120 V, 60 Hz. The resistance is 40 Ω and the capacitive reactance is 30 Ω. What is the capacitance of the capacitor? 37.89 μF 53.05 μF 66.31 μF 88.42 μF

88.42 μF

In an RC parallel circuit, the current flow through the capacitor will lead both the resistive current and applied voltage by _____. 60° 90° 180° 360°

90°

Which of these formulas is used to calculate capacitive current?

Ic=E/Xc

Which of these formulas would be used to calculate power factor?

PF=P/VA

Which is the formula for finding the quality of a capacitor?

Q=1/PF

The quality of a capacitor is found by Q = _____. XC/R R/XC PF W/VARs

R/XC

When a capacitor is connected in a circuit with a resistor, the amount of time needed to charge the capacitor is called the _____. CR time constant RC time constant CR time variable RC time variable

RC time constant

The _______________ indicates the amount of capacitance change with temperature.

Temperature Coefficient

Which of these formulas would be used to calculate impedance?

Z=........

In a series circuit, the current-limiting elements must be _____________. added subtracted multiplied divided

added

Variable capacitors normally have a dielectric of _____. air mica teflon glass

air

If a(n) ____________ were placed in an AC circuit, it would indicate a continuous flow of current, giving the appearance that current is flowing through the capacitor. ammeter ohmmeter voltmeter wattmeter

ammeter

In a capacitor, the voltage difference between the plates controls the _____. area of the plates thickness of the dielectric amount of dielectric stress amount of current flow through the capacitor

amount of dielectric stress

In a series RC circuit, ET = 240 V, R = 150 ?, and XC = 270 ?. What is the reactive power? 126.48 VARs 163 VARs 190.56 VARs 253.56 VARs

163 VARs

Two capacitors, a 20 μF and a 30 μF, are connected in series to a 60-Hz source. What is the total capacitive reactance? 117.96 Ω 221.04 Ω 253.05 Ω 333.16 Ω

221.04 Ω

In an RC parallel circuit, ET = 120 V, R = 300 Ω, and XC = 400 Ω. What is P? 20.57 W 36 W 48.8 W 58 W

36 W

Which is the formula for finding capacitance?

C=1/2piefC

Which of these formulas would be used to calculate voltage drop across the resistor?

C=1/2piefXc

Because the current flow in a pure capacitive circuit leads the applied voltage by 90°, the voltage and current have the same polarity for half the time during one cycle and have opposite polarities the other half of the time. True False

True

In a capacitive circuit, the voltage leads the current by 90 electric degrees. True False

False