Difference between watts and volt amperes

Ravi Barwad

10 years ago

Difference	Watts	Valt-amperes
Abbreviation	W	VA
Calculation	For dc: V_dc X I_dc	For dc: V_dc X I_dc
Instrument need for measurement	Wattmeter (a typical multimeter cannot measure watts unless the V and I are both dc)	Typical multumeter capable of measuring V_RMS and Ir_RMS.(VA = V_RMS X I _RMS)
Used for	Evaluating heat generated or dissipated and calculating cost of energy.	Properly sizing wires, circuit breakers, and fuses.
To add multiple rating together	Add W ratings linearly	No straightforward method to add VA, but if added linearly, result will be greater than or equal to actual total (adding linearly provides a conservative estimate)