- Watt is the unit of real power and
- VA is the unit of apparent power.
In a DC circuit, the real power(watt) and the apparent power(VA) are equal because the power factor of the DC circuit is unity.
In an AC circuit, the power factor is an important factor in deciding the apparent power(VA) and active or real power(watt) of the AC circuit. In an AC circuit, the relationship between the real power(watt) and apparent power(VA) can be expressed by:
Apparent power (VA) = real power (W) / power factor
By dividing the watt by the power factor, can able to calculate the apparent power(VA).
VA = W / pf
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