Alternating Current (A.C.)

Definition

• Current flow in conductors when electrons move, as opposed to static electricity.

Types of Current

• Direct Current (D.C.): Electrons flow in one direction, from negative to positive terminals of a power supply.
• Alternating Current (A.C.): Electrons oscillate or move 'back and forward' in a cycle.

A.C. Cycle

One complete A.C. cycle involves:

• Current initially rises from the origin to a peak.
• Then falling to reach the same but negative peak.
• Finally rising back to the x-axis.
• It comprises two halves with alternating current flow directions.

A.C. Waveform Visualization

• Oscilloscopes display A.C. waveforms.
  • Y-axis: Voltage across a component.
  • X-axis: Time changes.

Quantities Determined by Oscilloscope

Oscilloscope trace helps find two key A.C. signal quantities:

• Frequency: How quickly the cycle repeats.
• Peak Voltage: The highest point reached in the cycle.

Why is A.C. Widely Used?

Transformers play a crucial role:

• They increase and decrease voltages in A.C. supply networks.
• This reduces current flow in transmission lines.
• Saves energy when supplying electricity over long distances.

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Alternating Current (A.C.)