What is the difference between WATTS and VA?

Answer 1

We know that Power = Voltage(V) X Current(I) and power is measured in terms of watts as well as volt-amperes. However, for AC circuits, based on the observation that the voltage considered is often an average measure, VA often tends to be a far higher number as compared to the actual "wattage".

Based on some information I found at the Argonne national laboratory site:

the explanation found was:

1 joule = the energy generated when 1 ampere of electrical

current, passes through an electrical potential drop of 1 volt. Energy =

Volts x Current.

1 watt = 1 joule/second.

So joules is a quantity of energy, and watts is the RATE of generation of

energy. Watt = Energy / second.

Answer 2

In a DC circuit, the power in watts is the volts times the amps. In an AC circuit, the volts times the amps is called the VA, and the power in watts is the VA times the power factor, which is 1 for some appliances but less than 1 for others.

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volt-amps, or current, is only one variable of any circuit; wattage would be the product of current times voltage, a.k.a. power

Answer

In purely-resistive AC circuits, the load current and supply voltage are said to be in phase with each other, and the product of these two quantities is called the true power of the load, expressed in watts.

If the AC circuit is not purely resistive, then it is described as being reactive, and the load current either lags or leads the supply voltage. In this case, the product of these two quantities results, not in the true power of the load, but in the apparent power of the load. To differentiate between apparent power and true power, apparent power is measured in volt amperes (V.A) while true power is measured in watts (W).

The cosine of the angle by which the load current leads or lags the supply voltage in reactive loads is called power factor, and has to be taken into account when calculating the true power of the circuit -so, in this case, true power is the product of supply voltage, load current, and power factor.

To summarise, volt amperes are used to measure the apparent power of a reactive load, while watts are used to measure its true power.

Answer 3

The watt is used to measure the true power of an a.c. load. It is the product of the supply voltage, the load current, and the power-factor of the load.

The volt ampere is used to measure the apparent power of an a.c. load, which is the product of the supply voltage and the load current.

Answer 4

Watts (W) measures real power consumed by a device, while volt-amperes (VA) represent apparent power used by the device. The power factor is the ratio of real power (W) to apparent power (VA), and it accounts for the difference between the two measurements in imperfectly matched loads.