Alternating current

Definition

Alternating current (AC) is an electric current that reverses its direction periodically, contrasting with direct current (DC), which flows in a single direction. This periodic reversal allows for more efficient transmission of electricity over long distances and is the standard form of electrical power used in homes and businesses.

5 Must Know Facts For Your Next Test

1. Alternating current is measured in Hertz (Hz), which indicates the number of cycles per second; for example, in North America, the standard frequency is 60 Hz.
2. AC power can be easily transformed to higher voltages for transmission, which reduces energy loss and allows electricity to travel long distances more efficiently.
3. The invention of the AC motor by Nikola Tesla was crucial for the widespread adoption of alternating current as it enabled practical uses in appliances and machinery.
4. Household appliances and lighting systems are designed to operate on alternating current due to its ability to be easily converted and managed through electrical systems.
5. In contrast to direct current, which can result in power loss over distances due to resistance, alternating current's ability to change voltage levels significantly enhances its efficiency.

Review Questions

• How does alternating current differ from direct current in terms of flow and application?
  • Alternating current differs from direct current primarily in the direction of flow; AC periodically reverses direction while DC flows consistently in one direction. This characteristic of AC makes it more suitable for power distribution systems as it can be transformed to different voltage levels easily, facilitating long-distance transmission. Additionally, most household appliances are designed to operate on AC due to its efficiency and adaptability.
• Discuss the role of transformers in the use of alternating current for electricity distribution.
  • Transformers play a critical role in electricity distribution by allowing alternating current to be adjusted to higher or lower voltages as needed. When AC electricity is generated, it is often produced at low voltage; transformers can increase this voltage for efficient long-distance transmission, minimizing energy loss. Upon reaching its destination, another transformer lowers the voltage to safe levels for use in homes and businesses. This capability is fundamental to modern electrical grids.
• Evaluate the impact of Nikola Tesla's contributions on the development and acceptance of alternating current systems.
  • Nikola Tesla's contributions significantly impacted the development and acceptance of alternating current systems by introducing practical applications such as the AC motor and transformer technology. His work demonstrated the advantages of AC over DC for power generation and transmission, leading to its adoption as the standard electrical system. Tesla's innovations not only facilitated efficient electricity distribution but also laid the groundwork for modern electrical engineering, influencing countless technologies we rely on today.

Related terms

Direct Current: A type of electrical current that flows in a single, constant direction, commonly used in batteries and electronic devices.

Voltage: The electric potential difference between two points, which drives the flow of electric current in a circuit.

Transformer: A device that changes the voltage of alternating current, allowing electricity to be transmitted efficiently over long distances.