In physics, power is a very important concept for the students.
Power is the result of the voltage and current. This concept is equally important in all branches of engineering, starting from mechanical to electrical to electronics engineering branches.
Active vs Reactive Power
The difference between the active and reactive power is that in the case of active power, the power is used in the circuit and reactive power the power is imaginary and is thought to be used in the circuit for subsidiary purposes. The active power is unidirectional, and on the other hand, the reactive power is bidirectional.
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The active power is the power that is used in the circuit. The active power exists in both AC and DC circuits. This power exists when the current is in phase with the voltage.
This power is seen flowing and can be measured, so it is called real power.
The reactive power is the power that travels from the emergence source towards the load and back from the load to the emerging power. The reactive power is the imaginary power in a circuit.
This power is imaginary as it is not known to be flowing. This power flows due to the reactive components in the circuit.
Comparison Table
| Parameters of Comparison | Active Power | Reactive Power |
|---|---|---|
| Definition | It is the power that travels from the source of emergence towards the load. | It is the power that travels from the emergence source towards the load and the returns back towards the source. |
| Direction | It is unidirectional that is travels in one direction. | It is bidirectional that is travels in both direction. |
| Circuits used in | It is used in both AC and DC circuits. | It is used only in SC circuits. |
| Use | This is used to convert the electrical energy into other forms of energy. | This does not convert but produces electric flux in the circuit. |
| Examples | Active power is used in toaster, heater, coffee machine, etc. | Reactive power is used in refrigerators, air condition, etc. |
What is Active Power?
In electrical and electronics the active power is a very important concept for basic knowledge. The active power is the power that is used in the circuit. The active power exists in both AC and DC circuits.
This power exists when the current is in phase with the voltage. This power is seen flowing and can be measured, so it is called real power.
When the term power is used, it is termed for the active power only. The unit of the active power is the same as that of power, which is ‘Watt’.
In the practical field of electrical power work, Kilowatt (kW) and Megawatt (mW) is used. The active power is measured in all circuits to understand the dissipated power from the circuit.
The symbol for the active power used is ‘P’. The formula for active power is P=V I cos ø, ‘ø’ is the angle between the phase between the current and voltage.
The active power is seen when the current is in phase with the voltage that is the ø is 0 degrees or 180 degrees. Active power is used to convert electrical energy into other forms of energy.
For example, electrical energy to luminance like in bulb, or electrical energy to optical, etc. Some devices that work in this principle are a toaster, heater, coffee machine, etc.
What is Reactive Power?
In the concept of power, reactive power is a power that is invisible but exists with that of real power.
The reactive power is the power that travels from the emergence source towards the load and back from the load to the emerging power.
The reactive power is the imaginary power in a circuit. This power is imaginary as it is not known to be flowing. This power flows due to the reactive components in the circuit.
The reactive power is the resultant power in the case of an AC circuit when the current is out of phase with that of voltage. This is mainly observed when the current is 90 degrees out of phase with the voltage.
This reactive power is bi-directional. That is, it flows from the emerging source towards the load and the load towards the emergence source.
Reactive power is a form of power, but the unit of this power is not expressed in watts. It is mainly expressed in ‘var’ in AC power systems.
The reactive power is expressed as ‘Q’. The formula of the reactive power is Q= V I sin ø. Here ‘ø’ is the phase angle between current and voltage, which is normally 90 degrees.
Main Differences Between Active and Reactive Power
- Active power is the power that travels from the source of emergence towards the load in contrast to that the reactive power is the power that travels from the emergence source towards the load and the returns back towards the source. It is the power that travels from the emergence source towards the load and returns back towards the source.
- Active power is unidirectional that is travels in one direction. On the other hand, the reactive power is bidirectional that is travels in both directions.
- Active power is used in both AC and DC circuits, whereas reactive power is used only in AC circuits.
- Active power is used to convert the electrical energy into other forms of energy in comparison to that reactive power does not convert but produces electric flux in the circuit.
- Active power is used in toasters, heaters, coffee machines, etc. on the other hand, reactive power is used in refrigerators, air condition, etc.
- https://ieeexplore.ieee.org/abstract/document/57998/
- https://ieeexplore.ieee.org/abstract/document/317674/
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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.
