# Unity Power factor in electrical circuit | formula & concept

We already have discussed the Power factor of an electrical circuit and how to calculate the power factor, etc. You might have heard the term unity power factor while dealing with the power in electric AC circuits. In this article, we are going to discuss the concept and formula of Unity Power factor of an electrical circuit.

1. What is Unity Power factor?
2. Is Unity power factor possible?
3. Formula of unity power factor
4. Physical significance of Unity Power factor

## Unity Power factor in a circuit

When the phase difference between the alternating current and voltage in an AC circuit is zero, then the power delivered in the circuit becomes maximum. At this condition, the power factor of the circuit becomes unity i.e. one (1). This power factor in a circuit is known as unity power factor.

## Is Unity power factor possible?

Yes, Unity power factor is possible. When the circuit is purely resistive, then the power factor of the circuit becomes unity. Because, the phase difference between alternating current and voltage in a purely resistive circuit is zero.

## Unity power factor formula

The formula of power factor is ${\color{Blue} f=cos\theta}$. Where, $\theta$ is the phase angle between the alternating current and voltage. Now, for unity power factor $\theta=0$. Then the formula of unity power factor is, ${\color{Blue} f=cos\theta=1}$.

## Physical significance of Unity Power factor

The power factor of a circuit cannot be unity if the circuit consists of any capacitor or inductor as a circuit component. So, the unity power factor of a circuit indicates that the circuit is purely resistive, it do not contain any capacitive or inductive reactance at the load. In this case, the apparent power is same as the actual power in the circuit.

This all from this article on Unity power factor in an electrical circuit. If you have any doubt on this topic you can ask me in the comment section.

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