AC Circuits: Active, Reactive, and Apparent Power

These flashcards cover key terms and concepts from the lecture on AC circuits, focusing on active, reactive, and apparent power, as well as circuit types.

Active Power

The average power consumed in an electrical circuit, calculated as P = VI cos φ, where V is voltage, I is current, and φ is the phase angle.

Reactive Power

The power that alternates between the source and the load due to reactance, measured in VARs (volt-amperes reactive) and represented by Q = VIsin φ.

Apparent Power

The product of the RMS values of voltage and current, measured in volt-amperes (VA), represented by S = VI.

Power Factor

The cosine of the phase angle (φ) between the voltage and current waveforms, representing the efficiency of power usage in the circuit.

Purely Resistive Circuit

A circuit where current and voltage are in phase, resulting in no reactive power.

Purely Inductive Circuit

A circuit where the current lags the voltage by 90 degrees, resulting in reactive power while the average power over a complete cycle is zero.

Purely Capacitive Circuit

A circuit where the current leads the voltage by 90 degrees, also resulting in zero average power over a complete cycle.

Instantaneous Power

The power at a specific instant in time, calculated as the product of instantaneous voltage and current.

Phasor Diagram

A graphical representation of the phase relationship between voltage and current in an AC circuit.

Voltage Leading

The condition in which the voltage waveform reaches its peak before the current waveform in an AC circuit, particularly in capacitive circuits.

Voltage Lagging

The condition in which the voltage waveform reaches its peak after the current waveform in an AC circuit, particularly in inductive circuits.