AC Final

A capacitor is considered fully charged after how many time constants?

5

Unity power factor is a power factor equal to

1

In a conductor rotating 360 degrees through a magnetic field, maximum voltage is induced as ______ degrees and 270 degrees rotation

90

Inductive current leads CEMF by ______ degrees

90

In a pure capacitive circuit, current leads the source voltage by

90 degrees

If an AC waveform is rectified and converted into DC, the voltage value that results is the

Average Value

The unit of inductance equal to the voltage induced per rate of current change

Henry

Unit of measurement for inductance

Henry

Unit of frequency

Hertz

Dividing source voltage by the total circuit current yields __________ in a resistive-capacitive circuit

Impedance

The total opposition to current in a circuit that contains inductance, capacitance, and resistance

Impedance

The percentage of magnetic lines of force created by one coil that cut the windings of the second coil

Coefficient of Coupling

A change in ________ causes a change in inductive reactance

Frequency

The number of cycles completed in one second is called?

Frequency

The thicker the dielectric, the __________ the voltage it can withstand

Greater

The value of impedance is always ___________ than that of reactance or resistance

Greater

The difference between true power and reactive power is that ______________ supplied to a resistive load is used to perform work or is dissipated as heat

True Power

The unit of measure for power of a resistor in an AC circuit

True Power

When the values of source voltage and total current are known, _______ in a series resistive-capacitive circuit can be calculated by multiplying the voltage and current

True Power

A solenoid is an electric output device that converts electrical energy into

Linear Mechanical Force

Sometimes referred to as glass capacitors

Mica Capacitors

Inductor usually covered in plastic with a conductor at each end for connecting or soldering into a circuit

Molded inductor

Is the effect of one coil inducing a voltage into another coil

Mutual Inductance

An inductor that has coils wound in such a manner that the inductance created by one coil turn is cancelled by an adjacent coil turn

Non inductive coil

Can be used in AC and DC circuits

Non-Polarized

Capacitive Reactance is measured in?

Ohms

The most commonly used capacitors used for motor start capacitors are

Oil filled Capacitors

New digital multimeters, will read the _______ voltage of an AC sine wave

RMS

The square root of the mean of the square of the instantaneous currents is the?

RMS

Inductive _____________ is the opposition of an inductor to current in an AC current

Reactance

In an inductive-resistive AC circuit, the power of the inductor is ____________ power

Reactive

Current can be calculated in inductive AC circuits by modifying Ohm's law to substitute inductive reactance (XL) for

Resistance

Only ___________ can dissipate power in an electrical circuit

Resistance

The _______ effect occurs when AC induces eddy currents into the conductor, which cause the electrons to be repelled toward the outer surface of the conductor

Skin

Dielectric ___________ strength is the amount of voltage a dielectric material can safely handle

Strength

A ________ can be used as a battery replacement because it has characteristics similar to those of a battery

Super Capacitor

Formula to find one time constant for an inductor?

T=L/R

Also called Wattless power where no work is performed

VAR's

Reactive power is measured in

VAR's

Usually use air as the dielectric

Variable Capacitors

An inductor that consists of two coils, one fixed and one moveable

Variometer

In a parallel resistive AC circuit, the _________ is used as the reference for all circuit parameters

Voltage

In a series/parallel resistive-capacitive circuit, _________ is used as the reference point for all components and devices

Voltage

Average voltage equals peak voltage times

.637

RMS voltage equals peak voltage times

.707

In the generation of a sine wave, 0 volts is induced into a rotating conductor at ______ degrees and 180 degrees rotaion

0

Capacitance of a circuit is affected by

1. Dielectric constant of the material 2. Surface area of the plates 3. Thickness of the material

RMS voltage equals average voltage times

1.1

In an inductive AC circuit, CEMF is ________ degrees out of phase with the source voltage

180

Maximum out-of-phase condition occurs when signals are _____ degrees out of phase

180

Inductive reactance is affected by the size of the inductor in Henry's and?

AC frequency

Half-cycle of a sine wave, either positive or negative

Alternation

The greater the ratio of inductive voltage drop to resistive voltage drop, the greater the

Angle theta

In a series resistive AC circuit, true power is equal to ____________ power or VA

Apparent

Opposition to electron flow by a capacitor

Capacitive Reactance

When frequency is changed, the only parameter directly affected is the ___________, while the other parameters are indirectly affected by the change

Capacitive Reactance

Dielectric ____________ is the ratio of the capacitance of a capacitor with a given dielectric to the capacitance of a capacitor with air as the dielectric

Constant

If angle theta and power in Watt's is known, the ________ function can be used to calculate the value of the source apparent power

Cosine

Power factor is equal to the ___________ of angle theta

Cosine

CEMF is created by a change in ___________, which is caused by a constantly changing magnetic field that cuts the windings of an inductor

Current

In a power resistive circuit, the voltage sine wave and _________ sine waves are in phase with each other in both the positive and negative alternations

Current

In a series resistive-capacitive circuit __________ is the same at all points for all components and devices

Current

Inductance opposes any change in

Current

_______ is used as the reference for all circuit parameters in a series resistive AC circuit

Current

Each complete waveform of 360 degrees is called?

Cycle

Inductance is affected by

Diameter, Shape, and Material

The breakdown of insulation between the plates of a capacitor

Dielectric Breakdown

A term used to indicate the same value as the RMS value is the _________ value

Effective

The ____________ value of AC voltage is the value of a sine wave that produces the same amount of heat as DC of the same value

Effective

In a capacitive circuit, __________ only when a capacitor is charging or discharging

Electrons Flow

Capacitors can be connected together in parallel so that their capacitance?

Increases

Abrupt removal of power from a circuit often causes coils to fail because of

Inductive kick

Opposes a change of current

Inductor

Passive device that stores energy in the form of a magnetic field

Inductor

The ________ value of AC voltage equals the sine of the angle rotation times the peak voltage value

Instantaneous

Capacitive reactance is ____________ proportional to frequency

Inversely

Capacitive voltage _________ source voltage at all times in a capacitor only closed-loop circuit

Is equal to the

The small amount of current that flows through insulation

Leakage Current

A _________ capacitor has thin sheets of metallic foil, which act as plates, seperated by waxed paper which acts as the dielectric

Paper

An electrolyte in a capacitor can be in the form of a liquid or?

Paste

The____ value of AC voltage is the voltage from base to the maximum voltage

Peak-to-Peak

Has separate negative and positive connection leads

Polarised Capacitor

A _______ curve is a graph that shows the changes in circuit power as AC parameters, voltage, and current change over time

Power

In an AC system _________ is used as the reference for all circuit parameters

Power

The ratio of true power to apparent power

Power Factor

A __________ must be used to measure reactive power and true power in an AC circuit

Power Quality Meter

Time curve for current in an inductive-resistive circuit

Power curve

Inductive circuit has both resistance and inductance

Practical

When AC voltage is rectified and converted into DC, the resulting waveform is normally not pure, flat DC. The pulses that occur are called?

Ripples

AC voltage is most commonly made by

Rotating Machines

The property of a conductor to induce voltage within itself due to changes in current

Self Induction

The time required for current in an inductive-resistive circuit to reach 63.2% of its maximum value after power is applied

Time Constant

Time required to produce one complete cycle of a waveform

Time Period

A resistive-capacitive ______ is the amount of time required for the capacitor to charge to 63.2% of the maximum voltage across the circuit

Time constant

It takes 5 _________ for current to reach its maximum value in a LR circuit

Time constants

What type of coils are used for current transformers?

Toroid Coils

Electrical devices that use electromagnetism to step up or down voltage from one level to another and make AC more practical than DC

Transformers

Under normal conditions in power circuits, _________ power factor, a power factor of 100%, is the most desirable condition

Unity

True power is measured in

Watts

The distance covered by one complete cycle of a given frequency of sound as it passes through the air

Wavelength