Learning Objectives:

- Define Alternating Current (AC)
- Describe the characteristics of AC
- Understand the difference between AC and DC

Introduction to Alternating Current (AC): Alternating current (AC) is a type of electrical current that reverses direction at regular intervals. AC is widely used for transmitting and distributing electrical power to homes, businesses, and industries. Unlike direct current (DC), which flows continuously in one direction, AC constantly changes direction, oscillating back and forth in a sine wave pattern. AC is measured in units of frequency (Hertz or Hz), which represents the number of complete cycles per second.

Characteristics of AC:

- Periodic changes in direction: AC constantly changes direction, oscillating back and forth in a sine wave pattern.
- Amplitude: AC voltage varies in amplitude, reaching its maximum value at the peak of the wave and decreasing to zero at the zero-crossing points.
- Frequency: AC is measured in units of frequency (Hertz or Hz), which represents the number of complete cycles per second.
- Phase: AC voltage can be shifted in phase, meaning that the peak of one wave does not necessarily coincide with the peak of another wave.
- Power transmission: AC is used for power transmission and distribution due to its ability to be easily converted to different voltages using transformers.

Difference between AC and DC: The main difference between AC and DC is the direction of the flow of electrons. DC flows continuously in one direction, whereas AC constantly changes direction. DC is typically used for low voltage applications such as batteries and electronic devices, while AC is used for high voltage applications such as power transmission and distribution.

Conclusion: AC is an important type of electrical current used for transmitting and distributing electrical power. It constantly changes direction, oscillating back and forth in a sine wave pattern, and is measured in units of frequency (Hertz or Hz). Understanding the characteristics of AC is essential for designing and analyzing AC circuits, and for choosing the appropriate electrical components for a given application.