What is the definition of "period"?
The reciprocal value of frequency. Period measures the amount of time for one cycle.

## Electrical Systems Training

Class Information
 Tooling U classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
 Class Name: AC Fundamentals 210 Description: This class introduces the concept of alternating current (AC) and describes the variables that measure AC power. Prerequisites: 550110  550115  550120 Difficulty: Intermediate Number of Lessons: 15 Language: English, Spanish

Below are all the competencies and job programs that contain the class AC Fundamentals 210. Job programs are our traditional class lists organized according to common job functions. Competencies are our latest job-specific curricula that help tie online learning to practical, hands-on tasks.

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Competencies

Class Outline
• Objectives
• What Is Alternating Current?
• The Oscilloscope
• How AC Flows
• Common AC Waveforms
• The AC Generator
• Sine Wave Characteristics
• Current, Voltage, and Impedance in AC
• Frequency and Period
• Using the Sine Function
• Measuring Sine Waves
• Root Mean Square (RMS)
• Power in AC
• Summary

Class Objectives
• Distinguish AC from DC.
• List the advantages of AC.
• Describe uses of an oscilloscope.
• Describe the flow of AC.
• Identify types of AC waveforms.
• Describe how a generator creates AC.
• Identify sine wave measurements throughout its cycle.
• Describe Ohm’s Law variables in AC.
• Distinguish between frequency and period.
• Describe how the sine function is used for AC calculations.
• Describe amplitude and its related values.
• Describe RMS value.
• Describe how to produce true power in AC.

Class Vocabulary

Vocabulary TermDefinition
A branch of math that uses known quantities to find unknown quantities. In algebra, letters are sometimes used in place of numbers.
Current that regularly reverses the direction of its flow in a repeating, cyclical pattern.
A measurement of the size of a wave. Amplitude is also referred to as magnitude.
An electrical terminal that usually carries a positive electrical charge.
The rotating portion of a generator that passes through magnetic fields to generate current.
Stationary conductive devices which contact the slip rings on each end of the armature. The brushes conduct AC to the load so the current can perform work.
An AC electrical load in which the current wave reaches its peak before the voltage.
An electrical terminal that usually carries a negative electrical charge. An oscilloscope uses a cathode at the end of a cathode ray tube, which heats up and emits electrons.
An analog display device using a vacuum tube that generates images on a layer of phosphors driven by an electron beam.
A variable that remains unchanging.
A single increment of something that occurs repeatedly. AC flows in cycles of 360 electrical degrees.
Characterized by a cycle. One complete AC cycle is 360 electrical degrees.
A unit of measurement for angles and circular motion. Degrees expresses the amount of rotation in a sine wave.
Current that travels in one direction. Direct current does not reverse the direction of flow.
A DC value that is given as the equivalent of an AC value. An effective value is the value that DC would have to produce to have the same effect as an AC value.
A measure of the energy output of a system versus the total energy supplied to it. Maximum efficiency is achieved with a linear load.
A unit of measurement for expressing the amount of rotation in a generator and the position in an AC sine wave.
The process in which current is induced in a magnetic field using a current-carrying coil. An AC generator uses electromagnetic induction.
A measurement of the number of complete AC cycles that occur in one second. Frequency is measured in Hertz (Hz).
A device that converts mechanical energy into electrical power.
The unit used to measure frequency. Hertz expresses the number of complete AC cycles per second.
The resistance to current flow in an AC circuit.
The phrase used to describe a linear load. AC is described as "in phase" when both waves reach their peak simultaneously.
An AC electrical load in which the voltage wave reaches its peak before the current.
An AC electrical load in which both current and voltage waves reach their peak simultaneously. Also referred to as "in phase", linear loads are necessary to achieve maximum efficiency.
A waveform that is graphically represented with straight lines. A triangle wave is an example of a linear wave.
A component in a circuit that converts electricity into light, heat, or mechanical motion. Examples of loads are a light bulb, an appliance, or a machine.
A force of attraction that surrounds magnets and current-carrying conductors.
The area in and around a magnet that exhibits the powers of attraction and repulsion. Rotating an armature through lines of magnetic flux induces AC.
The size of a wave. Graphically, magnitude is the highest positive point on the wave and is the maximum positive voltage value.
The highest voltage value that a given wave reaches. The maximum voltage is equal to the peak amplitude of a wave.
The lowest negative point on a wave. The negative peak value is equal to the lowest voltage of the wave.
An electronic device that generates a high frequency.
A device that produces a visual trace of a voltage or current wave shape, generally on a cathode ray tube. AC waves can be viewed graphically on an oscilloscope.
The highest or lowest point on a wave.
The highest amplitude value on a wave. Peak amplitude can be negative or positive.
The lowest negative point on a wave. The peak negative voltage indicates the maximum negative voltage of the wave.
The highest positive point on a wave. The peak positive voltage indicates the maximum positive voltage of the wave.
A measurement from the negative peak value to the positive peak value.
The reciprocal value of frequency. Period measures the amount of time for one cycle.
A type of screen that uses phosphorous to project an electron beam. An oscilloscope uses a phosphorescent screen to project graphic representations of AC waveforms.
Having two oppositely charged poles, one positive and one negative. Polarity determines the direction in which current tends to flow.
One of two ends of the axis of a sphere. Poles also refer to the opposite ends of a magnet.
The highest positive point on a wave. The positive peak value is equal to the highest voltage of the wave.
The amount of work accomplished within a given period of time. With electricity, power is the product of current and voltage and is measured in watts.
A ratio of the average power available and the actual amount of power used. Power factor is an indication of efficiency.
The inverse of a given value. The reciprocal is equal to 1 divided by the number.
Characterized by a varying value. Unlike the constant values of DC, the average value of an AC output constantly ripples.
An abbreviation for root mean square. RMS is the formula used to determine the effective value of an AC sine wave.
The effective value of AC. RMS is the value that DC would have to produce to have the same effect as an AC value and is determined using the root mean square (RMS) formula.
The formula used to determine the effective value of an AC sine wave. RMS is equal to the peak value multiplied by 0.707.
A type of AC waveform that is produced by electronic test devices. The sawtooth wave rises and falls in straight lines.
In a right triangle, the ratio of the side opposite an angle and the hypotenuse of the triangle. In AC, the voltage of a sine wave is equal to the peak voltage multiplied by the sine of the angle of rotation.
The most common type of AC waveform. A sine wave consists of 360 electrical degrees and is produced by rotating machines.
A conductive device attached to the end of an armature that conducts current to the brushes.
A type of AC waveform that is produced by an oscillator. As voltage changes, current changes direction in the square wave.
In electricity, a phrase used to describe voltage adjustment. To step down voltage means to decrease voltage.
In electricity, a phrase used to describe voltage adjustment. To step up voltage means to increase voltage.
A type of AC waveform that is linear. The voltage for a triangle wave rises at a constant rate with time.
The branch of mathematics that addresses the measurements and relationships of a triangle and its parts. AC circuit calculations require knowledge of trigonometry.
The result of both current and voltage reaching their peak simultaneously. True power is a measurement of the rate at which electricity performs work such as producing heat, light, or mechanical energy.
The absence of matter. A cathode ray tube contains a vacuum with a cathode and one or more anodes.
The amount of voltage needed to push a given amount of current through a given amount of resistance.
A graphic representation of the flow of alternating current. The shape of an AC wave depends on the method by which the current was produced.
The type or shape of wave produced by AC. Waveform depends upon the angle which a rotating armature cuts through lines of magnetic flux.