# AC Circuits

ET 120

## Course Description

Prerequisite: ET 100 and ET 110, both with a minimum grade of "C". Introduces the basic concepts of electricity as it applies to AC circuits. Explains inductance, capacitance, and the phasor relationships between electrical signals. Explains the schematic symbols for devices used in AC circuits. Determines the total impedance for series and parallel combinations of resistors, inductors, and capacitors. Uses Ohm’s law, Kirchhoff’s voltage law, and Kirchhoff’s current law to solve combination AC circuits using phasor analysis. Also covers include series and parallel resonant frequencies, harmonics, filters, and time constants. Uses oscilloscopes and meters during lab activities to apply concepts learned during class. Credit may be earned in SKET 120 or ET 120 but not both. (30-15)

## Outcomes and Objectives

### Demonstrate an understanding of electrical terminology and scientific theory for AC circuits.

#### Objectives:

• Explain the basic concepts of magnetism, electromagnetism, flux density, magnetic field intensity, saturation, and hysteresis.
• Explain the basic operation of generators as a source of AC electricity.
• Associate basic electrical terms, units, and abbreviations with their meanings.
• Describe the concepts of AC voltage, current, resistance, reactance, and impedance.
• Differentiate between the equations used for AC and DC circuits.
• Apply the phasor representation of electrical signals to AC circuits. Analyze the phasor diagram to contrast leading and lagging electrical signals.

### Describe characteristics and perform calculations for AC circuits.

#### Objectives:

• Recognize and draw the schematic symbols for devices used in AC circuits. Differentiate between different symbols, conventions, and terminology.
• Calculate inductive reactance, capacitive reactance, and impedance for AC circuits.
• Utilize voltage, current, resistance, power, energy, and efficiency relationships to solve for AC circuit values.
• Analyze series, parallel, and combination AC circuits using phasor analysis.
• Differentiate between Ohm’s Law, Kirchhoff’s voltage law, and Kirchhoff’s current law. Utilize the appropriate laws and theorems to write loop equations and node equations.
• Calculate the resonant frequency for series and parallel LC circuits.
• Identify the fundamental frequency for a signal and the harmonics required to create other waveforms.
• Perform calculations to determine bandwidth and criteria for high and low pass filter design.
• Analyze the response of inductors and capacitors in DC circuits. Calculate time constants to determine the response of the system.

### Conduct laboratory experiments to reinforce lecture material.

#### Objectives:

• State, comprehend, and comply with safety precautions when working on electrical equipment.
• Construct circuits using electrical components and laboratory equipment. Calculate, measure, and analyze characteristics of AC circuits.
• Measure electrical values of current, voltage, and impedance in AC circuits.
• Develop troubleshooting techniques.