Power factor is generally used with regard to AC circuits irrespective of if it is single phase or three phase. Unlike AC circuits, in DC circuits one can simply determine the power by multiplying the readings of the voltmeter and ammeter connected in the circuit.

To determine the true power, a wattmeter is introduced in the circuit to measure the true power. The ratio of active power to apparent power is called power factor.

## Key Takeaways

- A leading power factor occurs when the current waveform leads the voltage waveform in an electrical circuit, which is typical in capacitive loads.
- A lagging power factor happens when the current waveform lags behind the voltage waveform, which is common in inductive loads such as motors or transformers.
- Leading and lagging power factors describe the phase relationship between current and voltage in electrical circuits. Still, they represent opposite-phase relationships and are associated with different types of loads.

**Leading vs Lagging Power Factor**

The difference between Leading and Lagging Power Factor is that the leading power factor is used to describe the situation where the load current leads the supply voltage whereas the lagging power factor is used to describe the situation where the load current lags behind the supply voltage.

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Also, the power factor always varies between 0 to 1. It can be determined by the lag or lead of load more in regard to supply voltage.

## Comparison Table

Parameters of Comparison | Leading Power Factor | Lagging Power Factor |
---|---|---|

Definition | Leading Power Factor is a term which is used where the load current leads the supply voltage. | Lagging Power Factor is a term which is used where the load current lags behind the supply voltage. |

Phase angle | In relation to the driving voltage phase angle, the resulting current phase angle is positive. | In relation to the driving voltage phase angle, the resulting current phase angle is negative. |

Significance | Leading power factor in an AC circuit signifies that the load current is capacitive. | Lagging power factor in an AC circuit signifies that the load current is inductive. |

Correction | To correct a leading power factor, inductive loads must be added. | To correct a lagging power factor, capacitive loads should be added. |

Examples | Radio circuits, electric motors, power supplies are some examples of capacitive loads. | Repulsion induction motors, power generators, relays are some examples of inductive loads. |

## What is Leading Power Factor?

Leading power factor is used to describe the situation where the load current leads the supply voltage. It is a property of an electric circuit that determines if the load current is capacitive.

A positive power factor is the power factor of a leading current. It is sometimes called positive power factor.

To sum it up, to get a leading power factor, the load has to be capacitive.

## What is Lagging Power Factor?

Lagging power factor is used to describe the situation where the load current lags behind the supply voltage. It is a property of an electric circuit that determines if the load current is inductive.

To correct a lagging power factor, capacitive loads should be added to the circuit. The most common form of three phase motors is the repulsion induction motor which is an inductive load and always has a lagging power factor.

The current that reaches its peak value that is up to 90 degrees later then the supply voltage can be generally described as lagging power factor.

All the AC motors except the overexcited synchronous motors and transformers operate at lagging power factor. Repulsion induction motors, power generators, relays are some examples of inductive loads.

**Main Differences Between ****Leading and Lagging Power Factor**

**Leading and Lagging Power Factor**- Leading power factor is used to describe the situation where the load current leads the supply voltage whereas lagging power factor is used to describe the situation where the load current lags behind the supply voltage.
- In relation to the driving voltage phase angle, the resulting current phase angle of leading power factor is positive while the resulting current phase angle of lagging power factor is negative.

**References**

- https://journals.sagepub.com/doi/pdf/10.1177/002072096500300414
- https://safetyclimate.sites.tamu.edu/wp-content/uploads/sites/96/2016/05/Payne-et-al.-2009-Safety-climate-Leading-or-lagging-indicator-of-safety-outcomes.

Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.